EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, apex multicellular, xylem exarch, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem multicellular, interface specific plasmodesmatal network; stem with ectophloic eustele, endodermis 0, xylem endarch, branching exogenous; vascular tissue in t.s. discontinuous by interfascicular regions; vascular cambium + [xylem ("wood") differentiating internally, phloem externally]; wood homoxylous, tracheids +; tracheid/tracheid pits circular, bordered; sieve tube/cell plastids with starch grains; phloem fibers +; stem cork cambium superficial, root cork cambium deep seated; nodes ?; stomata ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral, veins -5 mm/mm² [mean for all non-angiosperms 1.8]; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores, i.e. no distal pore for release of gametes] +, grains mono[ana]sulcate, exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, with cell walls, with many flagellae; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large", first cell wall of zygote transverse, embryo straight, endoscopic [suspensor +], short-minute, with morphological dormancy, white, cotyledons 2; plastid transmission maternal; two copies of LEAFY gene, PHY gene duplication [N/O//A/C and P//BE lines], mitochondrial nad1 intron 2 and coxIIi3 intron present.

MAGNOLIOPHYTA

Plant woody, evergreen; lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], lignins derived from both coniferyl and sinapyl alcohols, containing syringaldehyde [in positive Maüle reaction, syringyl:guaiacyl ratio less than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0; stem with 2-layered tunica-corpus construction; wood fibers and wood parenchyma +; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides; tracheids +; sieve tubes eunucleate, with a sieve plate and cytoplasm with P-proteins, companion cells from same mother cell that gave rise to the sieve tube; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm², endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, development in general centripetal, numbers unstable; P not sharply differentiated, outer members not enclosing the rest of the bud, smaller than inner members; A many, with a single trace, introrse, filaments stout, anther ± embedded in the filament, tetrasporangiate, dithecal, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally by action of hypodermal endothecium, endothecial cells elongated at right angles to long axis of anther; tapetum glandular, binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous or microperforate, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; nectary 0; G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, [outer integument often largely subdermal in origin, inner integument dermal], micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte four-celled [one-modular, nucleus of egg cell sister to one of the polar nuclei], stylulus short, hollow, stigma ± decurrent, dry [not secretory]; P deciduous in fruit; seed exotestal; pollen germinating in less than 3 hours, tube elongated, growing at 80-600 µm/hour, with callose plugs and callose-based walls, penetrating between cells, siphonogamy, penetration of ovules within ca 18 hours, distance to first ovule 1.1.-2.1 mm; double fertilisation +, endosperm diploid, cellular [first division oblique, micropylar end initially with a single large cell, chalazal end more actively dividing], copious, oily and/or proteinaceous, embryo cellular ab initio, minute; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and PHYA/PHYCgene pairs.

Evolution. Possible apomorphies for flowering plants are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable variation between families in particular for several of these characters, and also because details of relationships among gymnosperms will affect the level at which some of these characters are pegged. For example, if reticulate-perforate pollen is optimized to the next node on the tree (see Friis et al. 2009 for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous....

NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: vessels +, elements with scalariform perforation plates, axial parenchyma diffuse or diffuse-in-aggregate; tectum reticulate-perforate [here?]; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

CARYOPHYLLALES + ASTERIDS: seed exotestal; embryo long.

See the Dilleniales page for discussion on the relationships of these groups, which have no firm position as yet, although it is increasingly likely that Caryophyllales are close - perhaps even sister - to the asterids.

CARYOPHYLLALES Perleb  Main Tree, Synapomorphies.

(Odd ecology and/or physiology); plant not mycorrhizal; root hair cells in vertical files [sampling!]; (tracheids +); perforation plates not bordered; only alternate vascular pitting; scanty vasicentric parenchyma; both uni- and multiseriate rays present; leaves entire; anther with outer parietal cells developing directly into the endothecium, pollen colpate, tectum spinulose; G [3], when G = K or P, opposite them, micropyle endostomal, style branch long; fruit a loculicidal capsule; seed testal; embryo long. - 34 families, 692 genera, 11155 species.

Evolution. Caryophyllales contain ca 6.3% of eudicot diversity (Magallón et al. 1999) and may date to the Albian, 111-104 million years before present, although Rhabdodendraceae do not split off until 90-83 million years before present (Wikström et al. 2001); Anderson et al. (2005: Rhabdodendraceae also included) suggests figures of 116-114 million years before present for stem group Caryophyllales, 102-99 million years before present for the crown group. The Droseraceae et al. and Simmondsiaceae et al. clade may have diverged 90-83 million years before present, the two main groups in it in turn diverging 82-76 million years before present (Wikström et al. 2001). However, if Rhabdodendraceae are sister to the Simmondsiaceae et al. clade (see below), these estimates may need revising. Some chrysomelid beetles - Alticinae, Cassidinae-Hispinae - seem notably more common on this clade than others (Jolivet & Hawkeswood 1995).

Chemistry, Morphology, etc. Cuénoud (2002a, b) summarizes variation in the order. There are many unusual characters here, but their phylogenetic significance is unclear, partly because of sampling problems; e.g. knowledge of anther wall development is poor (Dahlgren & Clifford 1982). Furthermore, members of the basal pectinations in the clade immediately below core Caryophyllales are particularly poorly known. Given the variation in carpel number in the clade, it is with some hesitation that three carpels is suggested as the plesiomorphic condition.

Many families are tolerant of saline/arid conditions and/or have a distinctive habit (e.g. climbers with distinctive grapnel organs) or physiology (carnivory, C₄ pathway, CAM) or both. Landis et al. (2002) found that both Polygonales and Caryophyllales (here just the one order) commonly lack mycorrhizae, although there are some exceptions (e.g. some Nyctaginaceae and Amaranthaceae). For root hair development, see Dolan and Costa (2001). Isoflavonoids are scattered in the group (Mackova et al. 2006), perhaps especially in the core Caryophyllales. Flavonol sulphates occur in Plumbaginaceae, Polygonaceae, and Amaranthaceae (Chenopodiaceae s. str.), and sulphated betalains in Phytolaccaceae. Placement of several features of wood anatomy on the tree need checking (cf. Carlquist 2002b, 2003a). Non-bordered perforation plates may be a synapomorphy for Caryophyllales or Caryophyllales and Santalales (Carlquist 2000a). Anomalous secondary thickening by successive cambia is widespread, as are maximally biseriate rays (the latter inc. Asteropeiaceae, but not core Caryophyllales - Nandi et al. 1998). Similarities in sieve tube plastids between Triplarieae (Polygonaceae) and core Caryophyllales are here treated as parallelisms (cf. Judd & Olmstead 2004). The outer stamens are often initiated in pairs, especially in core Caryophyllales, but also elsewhere in the order (Ronse Decraene & Smets 1993); a petal and adjacent (antepetalous) stamen are developmental units in Plumbaginaceae and Caryophyllaceae (Friedrich 1956; Ronse Decraene et al. 1998). Trinucleate pollen is common. Carpels that are open in development are known both from Polygonaceae and core Caryophyllales (Tucker & Kantz 2001). The rpl23 gene is a pseudogene in the few Caryophyllales examined (Logacheva et al. 2008). Purple-spored smuts and Uromyces rusts parasitize several families, including Plumbaginaceae, Polygonaceae and core Caryophyllales (Savile 1979b: he considered this to be a strong sign that the groups were close).

Phylogeny. Hilu et al. (2003: matK analysis alone) suggest that Caryophyllales are sister to Asterids, a relationship that has been found in some other studies (e.g. Soltis et al. 1997, cf. also Nandi et al. 1998). A relationship between Caryophyllales and Dilleniales has also been suggested (D. Soltis et al. 2003a), see below for more details. However, Caryophyllales alone now seem to be sister to the asterids, although the support is still only moderate; see the Dilleniales page for further discussion.

Within Caryophyllales, Rhabdodendraceae are sister to the rest in the rbcL analysis of Fay et al. (1997b) and in the Bayesian analysis of Soltis et al. (2007a). Cuénoud et al. (2002) found that Simmondsia was grouped with Rhabdodendron in a matK analysis, but with only weak support, but in two- and four-gene analyses (with poorer sampling) it was associated with core Caryophyllales; in trees shown by Drysdale et al. (2007) and Brockington et al. (2007, esp. 2009) a position of Rhabdodendron as sister to the rest of core Caryophyllales was again found in most analyses, and is adopted here. Hilu et al. (2003: matK analysis alone) also suggested relationships between Rhabdodendraceae and this part of the tree. There are two main groups within Caryophyllales, the core Caryophyllales (with associated families) and Polygonaceae, etc. This latter clade, including Plumbaginaceae, Polygonaceae, Nepenthaceae, and Droseraceae, is well-supported (Morton et al. 1997b). It includes four carnivorous families (see also Albert et al. 1992; Meimberg et al. 2000; Cuénoud et al. 2002; Cameron et al. 2002) and other families with distinctive vegetative morphologies (see also Heubl et al. 2006). Within the other major clade, Asteropeiaceae and Physenaceae form a well supported pair, in turn showing a well-supported sister group relationship to core Caryophyllales (Källersjö et al. 1998). Similarly, Asteropeiaceae and Simmondsiaceae, the only two taxa from this part of the order that were included, were successively sister groups to the core (D. Soltis et al. 2000). The tree below is based largely on those presented by Meimberg et al. (2000), Cameron et al. (2002: 4 genes) and Cuénoud et al. (2002: matK alone). For relationships within the core Caryophyllales, see below.

Previous Relationships. Takhtajan's (1997) Plumbaginanae are monotypic; Nepenthanae included Droseraceae and some other Caryophyllales, but also families now in Ericales, etc. Many of the families in Caryophyllales were included in Cronquist's (1981) Caryophyllidae. Plumbaginaceae are rather similar in a few respects to Primulaceae and relatives and had been considered close (see Cronquist 1981 for discussion); Friedrich (1956) effectively discounted such ideas.

Includes Achatocarpaceae, Aizoaceae, Amaranthaceae, Anacampserotaceae, Ancistrocladaceae, Asteropeiaceae, Barbeuiaceae, Basellaceae, Cactaceae, Caryophyllaceae, Didiereaceae, Dioncophyllaceae, Droseraceae, Drosophyllaceae, Frankeniaceae, Gisekiaceae, Halophytaceae, Limeaceae, Lophiocarpaceae, Molluginaceae, Montiaceae, Nepenthaceae, Nyctaginaceae, Physenaceae, Phytolaccaceae, Plumbaginaceae, Polygonaceae, Portulacaceae, Rhabdodendraceae, Sarcobataceae, Simmondsiaceae, Stegnospermataceae, Talinaceae, Tamaricaceae.

Synonymy: Aizoineae Doweld, Basellineae Doweld, Cactineae Bessey, Caryophyllineae Bessey, Chenopodiineae Engler, Nyctaginineae Doweld, Phytolaccineae Engler, Portulacineae Doweld, Stegnospermatineae Doweld - Aizoales C. Y. Wu et al., Alsinales J. Presl, Amaranthales Dumortier, Ancistrocladales Reveal, Atriplicales Horaninow, Cactales Dumortier, Chenopodiales Dumortier, Dioncophyllales Reveal, Droserales Grisebach, Frankeniales Link, Illecebrales Berchtold & J. Presl, Mesembryanthemales link, Nepenthales Dumortier, Nyctaginales Dumortier, Opuntiales Willkom, Paronychiales Link, Petiveriales Lindley, Phytolaccales Doweld, Plumbaginales Lindley, Polygonales Dumortier, Portulacales Dumortier, Reaumuriales Lindley, Rhabdodendrales Doweld, Riviniales C. Agardh, Scleranthales Dumortier, Silenales Lindley, Simmondsiales Reveal, Staticales Link, Stellariales Dumortier, Tamaricales Hutchinson, Telephiales Link - Caryophyllanae Takhtajan, Nepenthanae Reveal, Plumbaginanae Reveal, Polygonanae Reveal, Rhabdodendranae Doweld, Simmondsianae Doweld - Caryophyllidae Takhtajan, Plumbaginidae C. Y. Wu, Polygonidae C. Y. Wu - Amaranthopsida Horaninov, Cactopsida Brogniart, Caryophyllopsida Bartling, Opuntiopsida Endlicher, Polygonopsida Brongniart, Plumbaginopsida Endlicher

Droseraceae group [Tamaricaceae + Polygonaceae groups]: acetogenic naphthoquinones +; endosperm starchy.

Chemistry, Morphology, etc. The acetogenic naphthoquinone plumbagin is known from Plumbaginaceae, Droseraceae, Nepenthaceae, and Dioncophyllaceae, and related compounds are found in Polygonaceae (Culham & Gornall 1994; Kovácik & Repcák 2006). It is unclear where the character of starchy endosperm is to be put on the tree. The condition is not known for the pectinations just below core Caryophyllales, and while Netolitzky (1926) noted that the core Caryophyllales lack starchy endosperm, and starch was not recorded from the thin endosperm found in the seeds of some Amaranthaceae (Shepherd et al. 2005b), Narayana and Lodha (1963) found starch in the young endosperm of Orygia (and Corbichonia: Lophiocarpaceae). In the Flora of China, several families of core Caryophyllales are reported to have starchy endosperm (e.g. Dequan & Gilbert 2003), but this must be a mistake.

Droseraceae [Nepenthaceae [Drosophyllaceae [Ancistrocladaceae + Dioncophyllaceae]]]: plumbagin +; plants carnivorous; vascularised multicellular stalked or sessile glands; inflorescence ± cymose; C contorted, anthers extrorse, ovary unilocular.

Evolution. The acquisition of carnivory may have happened more than once in this clade, or it occured once and then was lost, perhaps more likely given the topologies found (Meimberg et al. 2000; Cameron et al. 2002: see also Schlauer (1997). Heubl et al. (2006) suggest that fly-paper traps are the plesiomorphic condition for the group, but note that where features like this or the possession of circinate leaves and pollen tetrads are placed on the tree will depend on the mode of character optimisation used.

Phylogeny. Metcalfe (1952a) suggested relationships between members of this group based on anatomical similarities. Williams et al. (1994) drew atttention to possible relationships between Dioncophyllaceae and Drosophyllum in particular, and Drosophyllum and Nepenthaceae were also found to be weakly associated (Morton et al. 1997b). For detailed relationships, see Meimberg et al. (2000) and Cameron et al. (2002); Drosophyllaceae are sister to Dioncophyllaceae + Ancistrocladaceae, with good support, in an analysis of matK sequences, the position of Nepenthaceae being uncertain (Cuénoud et al. 2002). For a synapomorphy scheme for the whole group, see in part Albert and Stevenson (1996) and Meimberg et al. (2000: the floral characters listed are mostly plesiomorphies), but especially Heubl et al. (2006).

Chemistry, Morphology, etc. For acetogenic quinones and alkaloids, see Hegnauer (1986), Bringmann and Pokorny (1995) and Bentley (1998). For carnivory, see Lloyd (1942) and Juniper et al. (1989). Heubl and Wistuba (1997) suggested that both Droseraceae and Nepenthaceae had ploidy levels of 8 or 16, based on x = 5 or thereabouts.

DROSERACEAE Salisbury, nom. cons.   Back to Caryophyllales

Insectivorous rosette herbs; flavonols, ellagic acid +; cork?; young stem with separate bundles in one or two rings, medullary rays broad; cambium 0; (medullary bundles +); nodes 1:1; petiole bundles various; stomata also tetracytic or actinocytic; mucilage hairs with xylem only; leaves adaxially circinate, glandular, stipules intrapetiolar, ?cauline, or 0; inflorescence terminal, cyme monochasial, (bracts/bracteoles 0); K often connate at base, C ± marcescent, stamens = and opposite sepals (-15 - Dionaea), (introrse), (connective expanded), pollen in tetrads, bi- or trinucleate, intectate, 3-multiporate, operculate or not; G [3(-5)], median member abaxial, placentation parietal (basal - Dionaea), 3-many (tenuinucelllate) ovules/carpel, parietal tissue often absent, nucellar endothelium +, styles +, often bifid, (style + - Dionaea), stigmas expanded, papillate; (fruit indehiscent); exotesta palisade or not (endotesta with U thickenings), endotegmic cells small, ± sclerotic, or mucilaginous; embryo sac haustorium +, endosperm nuclear, (embryo short); (germination cryptocotylar); n = 5<, chromosomes 1.5³ µm (<6µm [Dionaea]); chloroplast rpl2 intron 0 [one species!].

3[list]/115: Drosera (110). World-wide (map: from Hultén 1971; George 1982; Correa A. & Silva 2005). [Photos - Collection, Collection.]

• Droseraceae are insectivorous herbs usually with adaxially coiled or folded leaves and moderate-sized flowers; there are three carpels usually terminated by branched styles.

Evolution. The beginning of diversification within Drosera may date to ca 42 million years before present, although a pre-continental drift origin has also been suggested (Yesson & Culham 2006 and references). Drosera is exceptionally diverse in SW Australia, which has about one third of the species in the whole genus; diversification may be linked to the onset of the Mediterranean climate there some 15-10 million years before present.

Aldrovandra and Dionaea both have snap-traps, multicellular trigger hairs, etc. (Cameron et al. 2002). The traps of Dionaea close in about 100 ms, the movement being aided by the leaf blades changing from concave to convex (Forterre et al. 2005); Volkov et al. (2008 and references) provide physiological details of the mechanisms involved while Gibson and Waller (2009) discuss the evolution of these snap traps, unique in angiosperms - perhaps associated with the capture of larger prey.

Chemistry, Morphology, etc. Metcalfe and Chalk (1950) describe remarkable vascular patterns in the inflorescence axis and petiole. Drosera aliciae appears to have young inflorescences (before flower buds are evident) that show abaxial circinate ptyxis... See Hegnauer (1966, 1989) for chemistry, Boesewinkel (1989) for ovule and seed anatomy, Hoshi and Kondo (1998) for chromosomes, Cutler and Gregory (1998) for general anatomy, Conran et al. (2007) for gland morphology, and Le Maout and Decaisne (1868), Baillon (1887), Kubitzki (2002d) and the Carnivorous Plants Database for general information.

Phylogeny. Aldrovandra and Dionaea may be sister taxa; both have snap-traps, n = 6, etc. (Cameron et al. 2002; Rivadavia et al. 2003: little support for the relationship); see also Williams et al. (1994) for phylogeny. Rivadavia et al. (2003) discuss the phylogeny of Drosera.

Synonymy: Aldrovandaceae Nakai, Dionaeaceae Rafinesque

Nepenthaceae [Drosophyllaceae [Ancistrocladaceae + Dioncophyllaceae]]: fibriform vessel elements +; rays 1-2 cells wide; cortical bundles in stem; petiole bundle(s) surrounded by massive sclerenchymatous ring with embedded vascular bundles; anthers basifixed.

Heubl et al. (2006) place a character, "petiole with cortical vascular bundles" at this node - see above!

NEPENTHACEAE Berchtold & J. Presl, nom. cons.   Back to Caryophyllales

Insectivorous, usu. viny; flavonols +, ellagic acid 0; cork pericyclic; (also medullary bundles +); (vessel elements with scalariform perforation plates); true tracheids +; large spirally-thickened cells in pith, pericycle, etc.; nodes 5-9:5-9; petiole bundle arcuate, wing bundles +; peltate glands +; leaves sessile, abaxially circinate, with involute blade and twining unbranched tendril terminated by pitchers, base broad; plant dioecious, inflorescence a raceme, bracts and bracteoles 0; P (3-)4, decussate, with large flat nectariferous glands adaxially; staminate flowers: A (4-)8-25, connate into a central column; pollen in tetrads, trinucleate, apertures indistinct; pistillode 0; carpellate flowers: staminodes?; G [(3-)4(-6)], placentation axile, many ovules/carpel, style short, stigma single, broad, papillate; seeds numerous, minute, exotesta with much thickened inner walls; endosperm +, nuclear; n = 40.

1[list]/90. Madagascar to New Caledonia (map: see Meimberg & Heubl 2006). [Photo - Leaf; Collection.]

• Nepenthaceae are insectivorous plants that are easy to recognise because of the lidded pitchers borne on the end of a twining prolongation of the leaf. The leaf base itself is broad, further widening to form a laminar portion that then narrows to form the twining portion. The plants are dioecious, the inflorescences are racemes, the flowers are rather inconspicuous, and the seeds are very small.

Evolution. Nepenthes is known fossil as pollen from Europe in the Eocene (Krutzsch 1989).

For the biogeography of Nepenthes, see Meimberg and Heubl (2006). Some analyses suggest that the Malesian Nepenthes (including species from New Caledonia and Australia) are derived from a stock represented by the extant extra-Malesian taxa, but different relationships are suggested by different genes.

The expanded part of leaf is developed from the leaf base, as in many monocots, the pitcher from the rest. How insects are trapped in the pitchers has long been unclear. Recent work suggests that the rim (peristome) of the pitcher is extremely wettable, and insects may aquaplane when they step on it, falling in to the pitcher below where they die and get digested; only when the rim is dry can insects walk on it easily, and then they may get trapped when they walk on to the wax-covered inner pitcher walls (Bohn & Federle 2004). Interestingly, the ant Camponotus schmitzi lives in close association with Nepenthes bicalcarata, and it can run across even the wetted rim. For the fauna of the pitchers, see Kitching (2000), while Pavlovic et al. (2007) discuss the physiology of lamina and trap.

Chemistry, Morphology, etc. The outer integument develops greatly after fertilisation and forms an exostome (Goebel 1933); there is a hair-pin bundle in the testa (Takhtajan 1988). The parietal cell in the ovule does not divide further.

For general information, see Cheek and Jebb (2001: almost a monograph), Kubitzki (2002d), McPherson (2008) and the Carnivorous Plants Database, for chemistry, see Hegnauer (1966, 1990), for anatomy, Metcalfe (1952a) and Pant and Bhatnagar (1977), for the fauna of the pitchers, see Kitching (2000), and for the trapping of insects, see Bohn and Federle (2004: aquaplaning common).

Phylogeny. For relationships within Nepenthes, see Meimberg and Heubl (2006).

Drosophyllaceae [Ancistrocladaceae + Dioncophyllaceae]: ?

DROSOPHYLLACEAE Chrtek, Slavíkovà & Studnicka   Back to Caryophyllales

Small woody insectivorous plants; chemistry?; cortical bundles inverted; ?nodes; ?stomata; petiole bundles three, arcuate, inverted, sclerenchyma ring?; mucilage hairs with xylem and phloem; leaves linear, abaxially circinate, with stalked glands in lines; flowers large, C contorted, ± marcescent; A 10, attachment?, pollen trinucleate, tectate, pantoporate; G [5], opposite the K, placentation basal, styles +, stigmas capitate; fruit septicidal; seeds operculate, exotesta not palisade, endotesta crystalliferous, with U thickenings, exotegmen thick-walled; endosperm ?, embryo short; germination cryptocotylar; n = 6, chromosomes ³15 µm long.

1/1: Drosophyllum lusitanicum. Southern Iberian Peninsula, Morocco (map: from Ortega et al. 1995). [Photos - Collection]

• Drosophyllaceae are subwoody carnivorous plants that may be recognised by their long, abaxially coiled leaves that have sticky, glandular hairs in long lines on their abaxial surfaces; these hairs are not sensitive. The flowers are relatively large and short-lived (they remain open only a single day), but the petals dry and persist around the capsule.

Evolution. For carnivory in Drosophyllum, see Plachno et al. (2009); the leaf produces a sweet (?attractive) scent. Although Drosophyllum looks quite delicate, it grows in very dry conditions and does not dry out fast; the mucilage on the tentacles is hygroscopic and make help the plant maintain a positive water balance (Adamec 2009).

Chemistry, Morphology, etc. Stem/leaf anatomy would repay investigation; both the cortical and petiole bundles appear to be inverted (Metcalfe & Chalk 1950, as Droseraceae). The flowers are relatively large; the stamens opposite the calyx are longest. Dehiscence of the fruit is down the ribs of the capsule and the valves are opposite the calyx.

For some anatomy, see Metcalfe (1952a), for ovule and seed, see Boesewinkel (1989), and for general information, see Kubitzki (2002d), McPherson (2008) and the Carnivorous Plants Database.

Ancistrocladaceae + Dioncophyllaceae: lianes; (acetogenic napthyl isoquinoline alkaloids +); cortical bundles 0; petiole with inverted bundles in sclerenchyma ring; stomata actinocyclic; A introrse.

Chemistry, Morphology, etc. For the distinctive napthyl isoquinoline alkaloids, see Bringmann (1986), Bringmann and Pokorny (1995), and Bringmann et al. (2008, and references); they are synthesised from polyketide precursors, not from aromatic amino acids.

ANCISTROCLADACEAE Walpers, nom. cons.   Back to Caryophyllales

Plant twining, or with grapnels along one side of the branch opposite the leaves; myricetin +, ellagic acid?; cork mid-cortical; nodes 3:3; cortical bundles 0; cortex with with elongated pitted sclereids, tissue band indistinct; petiole bundle annular and with wing bundles; leaves supervolute, with surface glands; flowers small, pedicels articulated; C basally connate; A (5) 10, whorl opposite petals larger, filaments ± connate basally and adnate to C, G [3(-4)], half or more inferior, with 1 basal hemitropous ovule, micropyle?, styles articulated with apex of ovary, stigmas hippocrepiform or pinnatifid, ?type; fruit a nut, K much enlarged; seed ruminate, exotestal?; endosperm cellular, cotyledons much folded; n = ?

1[list]/12. Tropical Africa to W. Borneo and Formosa (map: from van Steenis 1949a; Freson 1967; C. Taylor, pers. comm.). [Photo - Fruits] [Photo - Grapnels]

• Ancistrocladaceae are lianes that can be recognised by their shortly petiolate, extsipulate, entire leaves with glands in pits on the abaxial surface, and the complex, branched stem grapnels that are often opposite the leaves.

Chemistry, Morphology, etc. The pollen is like that of Dioncophyllaceae. Minute stipules and flowers with four carpels are reported by Takhtajan (1997) and Porembski (2002). 1/3 species tested had fluorescing wood. For anatomy, see Metcalfe (1952a), for chemistry, see Hegnauer (1989) and for general information, see Porembski (2002).

Previous Relationships. In the past Ancistrocladaceae have often been included in Theales or Theanae (Cronquist 1981; Takhtajan 1997).

DIONCOPHYLLACEAE Airy Shaw, nom. cons.   Back to Caryophyllales

Insectivorous lianes or shrubs with anomalous secondary growth; cyclopentenoid cyanogenic glycosides +, ellagic acid?; cork deep seated; xylem with included phloem; wood parenchyma vasicentric or apotracheal-diffuse; nodes ?; cortex with massive band of fibrous tissue; petiole bundle 1-3, arcuate; glandular hairs +; leaves abaxially circinate, first leaves with stalked glands, later leaves with paired, recurved hooks; K valvate or open; A 10-30, G [2, 5], placentation parietal, many ovules/carpel, (short style +), stigmas punctate, capitate or feathery; capsule opening before maturity; seeds flattened, on elongated funicles, winged or not, ?ruminate; coat ?; endosperm ?nuclear; n = 12, 18 [both Triphyophyllum peltatum]; germination epigeal, cryptocotylar.

3[list]/3. Tropical West Africa (map: only approximate).

• Dioncophyllaceae are distinctive in their rather long rosette leaves with closely parallel venation, these are followed by leaves with a short blade and glandular hairs on the abaxial surface of the prolonged midrib, and then, in the climbing phase, by leaves with paired grapnel hooks at the apex. The fruits open early and expose the still-developing flattened seeds.

Chemistry, Morphology, etc. For anatomy, see Metcalfe (1952a) and Miller (1975), for morphology, see Gottwald and Parameswaran (1968) and Schmid (1964), for chemistry, Hegnauer (1966, as Flacourtiaceae, 1989) and Spencer and Siegler (1985), for carnivory, Bringmann et al. (2001), and for general information, see Porembski and Barthlott (2002), McPherson (2008), and the Carnivorous Plants Database.

Previous Relationships. Dioncophyllales were included in Theanae by Takhtajan (1997).

[Frankeniaceae + Tamaricaceae] [Plumbaginaceae + Polygonaceae]: vessel elements with minute lateral wall pits +; sulphated flavonols, ellagic acid +; seed exotestal.

Chemistry, Morphology, etc. Sulphated pneholic compounds are found in seagrasses (McMillan et al. 1980), and here the plants with such compounds are often halophytic. Frankeniaceae, Tamaricaceae and Plumbaginaceae all have flat, multicellular glands of subepidermal origin (Conran et al. 2007). This is perhaps an apomorphy here (or still higher), with a loss in Polygonaceae; placing the characters on the tree is difficult.

Frankeniaceae + Tamaricaceae: halophytic; bisulphated flavonols +, myricetin 0; wood storied; nodes ?; ?SiO₂ bodies +; (stomatal orientation transverse); leaves small, with salt-excreting glands; flowers small, 4-6-merous, C with basal adaxial appendages, pollen not spinulose; G with median member abaxial, placentation (basal; intrusive-)parietal; fruit a capsule; exotestal cells bulging or as hairs; endosperm +.

Chemistry, Morphology, etc. For salt glands, see Fahn (1979).

Phylogeny. The monophyly of the two families and their sister-group relationship have recently been confirmed by Gaskin et al. (2004). It is equally parsimonious to assume that petal appendages are apomorphies for the family pair as it is to assume that they have evolved independently; in Tamaricaceae the Reamuria clade, members of which have these appendages, is sister to the rest of the family. Seeds with copious endosperm have the same distribution - optimization problems again.

Previous Relationships. Both Frakeniaceae and Tamaricaceae were placed in Violales by Cronquist (1981) and in Violanae by Takhtajan (1997), probably because of their parietal placentation.

FRANKENIACEAE Gray, nom. cons.   Back to Caryophyllales

Herbs to shrubs; cork pericyclic or subepidermal; fibriform vessel elements +; rays 0; cuticle wax crystalloids 0; leaves opposite, often ericoid; flowers also 7-merous, K connate, lobes induplicate-valvate, C clawed, A (3-)6(-24; inner whorl staminodial), slightly connate at the base or not, versatile, tapetal cells binucleate, pollen trinucleate; G [(2-)3(-4)], (1-)2-6(-many) tenuinucellate ovules/carpel, nucellar cap +, funicles long, style +, stigma surface branched; exotestal cells large, papillate, papillae with terminal nail-like thickenings, endotestal cells thin-walled [?fibers], endotegmen with thick cuticle, tanniniferous; micropylar endosperm haustorium +; n = 10, 15.

1/90: Frankenia. ± World-wide in warm, dry areas, but scattered (map: from George 1982; Whalen 1987; Jäger 1992; FloraBase 2004). [Photos - Collection]

Chemistry, Morphology, etc. There are no medullary rays. The endosperm has a coenocytic micropylar haustorium. Some information is taken from Walia and Kapil (1965), Whalen (1987: taxonomy Old World Frankenia) and Olson et al. (2003: anatomy); for general accounts, see Surgis (1921) and and Kubitzki (2002d).

TAMARICACEAE Link, nom. cons.   Back to Caryophyllales

Woody, also xeromorphic; (gypsum crystals +); cuticle waxes as tubes or curled rodlets; leaf bases often broad; inflorescence racemose (flowers solitary), bracteoles 0; K connate below or not, stamens = or 2x C or more, most connate at base into 5 bundles, borne with C surrounded by nectary (nectary inside or outside A, or 0), anthers variously attached; G [(2-)3-4(-5)], opposite petals, ovules 2-many/carpel, embryo sac tetrasporic [a variety of types, even in one species, often 16-nucleate bipolar], styles +, (style +, short), stigmas usu. expanded, wet; seeds with hairs, exotestal cells periclinally elongated and thick-walled, endotestal cells thin-walled, crystalliferous; endosperm usu. scanty, oil and protein as reserves, perisperm common, thin; n = (11) 12.

5[list]/90: Tamarix (55). Eurasia and Africa, esp. Mediterranean to Central Asia, commonly naturalised in North America (map: from Hultén & Fries 1986; Meusel et al. 1978). [Photos - Collection]

• Tamaricaceae are woody plants with small leaves and flowers; the styles are long and are terminated by distinctive expanded stigmas. The capsular fruits release hairy seeds.

Chemistry, Morphology, etc. Reamuria is distinctive in having single terminal flowers, a contorted corolla,and basal adaxial scales on the petals, c.f. Frankeniaceae. It also has many centrifugal stamens arising from 10 primordia, it lacks a nectary, and its seeds have endosperm (Ronse Decraene 1990). The nucellus is very thin, the parietal cell not dividing. See Hegnauer (1973, 1990) for chemistry, Czaja (1978) for seed storage, Zhang et al. (2001) for pollen and Gaskin (2002) for a general account.

Phylogeny. Relationships within the family are [[Holachna + Reamuria] [Myricaria + Tamarix]] (Gaskin et al. 2004).

Synonymy: Reamuriaceae Lindley

Plumbaginaceae + Polygonaceae: plants herbaceous; O-methylflavonols, myricetin, quinones +; (wood storeyed); successive cambia 0; cortical and/or medullary vascular bundles +; nodes 3:3; leaf bases broad; pollen usu. starchy; G with median member adaxial, 1 loculus and 1 basal ovule; fruit surrounded by accrescent calyx which forms part of the dispersal unit; exotesta ± persistent, otherwise seed coat undistinguished; mitochondrial coxII.i3 intron 0.

Evolution. Lycaeninae caterpillars are quite commonly found on this group, probably because of the polyphenolics in their leaves (Fielder 1995).

Chemistry, Morphology, etc. For sterol composition in comparison to that of core Caryophyllales, see Wolfe et al. (1989), for anatomy, see Carlquist and Boggs (1996).

PLUMBAGINACEAE Jussieu, nom. cons.   Back to Caryophyllales

Often salt tolerant; glycine betaine, choline-O-sulphate +, little oxalate accumulation; vascularized mucilage glands and epidermal glands +; cork subepidermal or cortical; secondary thickening odd; rays multiseriate; petiole bundles arcuate; cuticle wax crystalloids 0 (irregular platelets); stomata also paracytic; K connate, ribbed, C contorted, stamens = and opposite petals, pollen with irregular columellae, tectum continuous, itself with columellae, with rather coarse blunt spines, nectary often on adaxial side of filament bases; G [5], ovule anatropous, funicle long and curled, obturator from wall at apex of ovary, embryo sac tetrasporic, 4- or 8-nucleate, stigmas capitate or not, (multicellular papillae +); endotegmen persistent; endosperm 4n or 5n, little persisting, embryo green.

27[list]/836 - three groups below. Predominantly Mediterranean to Central Asia, scattered elsewhere. [Photos - Collection]

1. Plumbaginoideae Burnett

Herbs or shrubs; 5-O-methylated flavonols +; stems angled and striate; leaves (deeply lobed), petioles often short, (cauline stipules - Plumbago); inflorescence racemose, vegetative and reproductive shoots similar; (heterostyly +); K herbaceous, glandular, C (connate), lobes truncate-emarginate and then apiculate, style +, receptive areas in bouquet-like aggregations along branch; fruit a basally circumscissile capsule, calyx herbaceous; n = 6, 7.

4/36. East Asia and Africa, Plumbago pantropical (map: from Baker 1948, probably over-optimistic, Plumbago in particular commonly cultivated).

2. Staticoideae Kosteletzky

Plumbagin 0, glycine betaines rare, betaalanine betaines +; leaves cartilaginous, with 5-10 marginal rows of whitish cells; C connate, stamens adnate to corolla, (style ± developed), branches +, stigma capitate (filiform).

2A. Aegialitideae Peng

Shrublet; ellagic acid +; successive cambia +; cortical vascular bundles +; branched sclereids; leaves involute, basal sheath surrounding stem; fruit?; n = ?

1/2. Indo-Malesian, Australia, in mangroves (map: from van Steenis 1949c, in blue).

Synonymy: Aegialitidaceae Linczewski

2B. Staticeae Bartling

Herbs or shrubs; (glycine betaines), betaalanine betaines +; leaves more or less clustered at base, (deeply lobed), inflorescence leaves reduced or absent, petioles often short; inflorescence capitate or cymose, axis channelled, vegetative and reproductive shoots different; (heterostyly +), K scarious (also petaloid), pollen often dimorphic, columellae regular, tectum incomplete, reticulate; fruit an achene or circumscissile capsule; calyx scarious; n = 8, 9; deletion of rpl16 intron.

22/800: Limonium (350), Acantholimon (165), Armeria (90: half on the Iberian Peninsula). Mostly Irano-Turanian (Mediterranean), but also S. Africa, S. South America, and W. Australia (map: from Hultén; Baker 1948; FloraBase 2004).

Synonymy: Armeriaceae Horaninow, Limoniaceae Seringe, nom. cons., Staticaceae Cassel

• Plumbaginaceae are perennial herbs or shrubs, rarely climbers. They can be recognised by their leaves which have broad bases and are frequently only shortly petiolate and/or with entire margins, and their flowers which have a relatively large, persistent, and sometimes colored calyx (which can be scarious in fruit) and antepetalous stamens. The single ovules borne at the ends of long, curved funicles are easily enough seen on dissection.

Evolution. Members of the family prefer saline and sometimes rather dry conditions. In a number of Staticeae the calyx becomes scarious in fruit and helps in dispersal; in Plumbago the sticky calyx glands persist in fruit. Staticeae are most diverse in the area from the western Mediterranean (Limonium, etc., with hybridization and hundreds of microspecies, some apomictic) to Central Asia (Acantholimon, etc.), diversification in the family beginning perhaps as recently as 18-16 million years ago (Lledó et al. 2005).

Chemistry, Morphology, etc. Glycine betaine is known from only some species of Limonium (and from Plumbago), but not from Aegalitis and Armeria (Rhodes & Hanson 1993). Betaines are quaternary ammonium compounds that are involved in salt excretion. For wood anatomy, which may be paedomorphic, the family perhaps having a more or less herbaceous ancestry, see Carlquist and Boggs (1996). There is extensive gross anatomical variation that probably can be integrated with the tribes/subfamilies - for example, there is a continuous ring of sclerenchyma outside the phloem in Plumbaginoideae, separate fascicles in Staticoideae, etc. (see Maury 1886). Williams et al. (1994) suggested that it was not known if the mucilage glands were vascularized, although in their data matrix the family was scored as having such glands. Leaf vernation is variable, being flat, convolute or involute. Many Plumbaginoideae seem to lack a protruding obturator (Dahlgren 1916). The style branches of Armeria are papillate all around for their entire lengths. According to Dahlgren (1916), the embryo sac is tetrasporic but eight-nucleate. Aegalitis is little known.

Baker (1948, 1953) discussed variation in floral morphology (pollen, stigmas, etc.), de Laet et al. (1995) discuss floral development, Hegnauer (1969, 1990) chemistry, and there is much general information in Kubitzki (1993b).

Phylogeny. Lledó et al. (1998, 2001) suggest phylogenetic relationships within the group; these are consistent with the classification used here. For a phylogeny focusing on Limonium, see Lledó et al. (2005). It has also been suggested that Aegialitis may be sister to the rest of the family (Savolainen et al. 2000 - rbcL only); some of the characters attributed to Plumbaginaceae as a whole may need confirmation. There are a number of monotypic genera in Staticeae (Kubitzki 1993b).

Previous Relationships. Primulaceae used to be associated with Plumbaginaceae. Both have stamens opposite the petals, common petal-stamen primordia, and a ± connate corolla (the latter especially in Staticoideae), but the two are not close - for Primulaceae, see Ericales.

POLYGONACEAE Jussieu, nom. cons.   Back to Caryophyllales

Shoots monopodial, branching from previous flush; soluble oxalate accumulation; cork subepidermal (pericyclic); dark-staining deposits, esp. in rays; pits vestured; nodes also 5 or more:5 or more; petiole with a (D-shaped) ring of bundles, (bundles scattered - some Coccoloba); mucilage cells common; soluble calcium oxalate accumulation; cuticle waxes as platelets or rodlets; (stomata dia- aniso- or paracytic); leaves revolute (convolute - Muhlenbeckia; margins lobed), 2ndary veins also palmate, stipule sheathing stem ["ochrea"], colleters +; (plant dioecious), inflorescences with flowers in fascicles, flowers small, pedicels articulated; flowers basically 3-merous, hypanthium ± developed; P spiral (4, 6), basally ± connate, one with two veins, stamens = to and alternate with P to 3 x P, pollen tricolporate to pantoporate, nectary a disc, or between A; G [(2) 3 (4)], ovule atropous, (unitegmic), nucellar beak +, (archesporium multicellular), (style short), stigma ± penicillate or capitate; fruit a trigonous (lenticular) achene; endosperm ruminate or not, embryo straight to curved, lateral or not; expansion of the chloroplast inverted repeat.

43[list]/1110 - two groups below. World-wide (map: from Hultén 1971; FloraBase 2008; Tanya Schuster, pers. comm.). [Photos - Collection]

1. Polygonoideae Eaton

Shrubby, vines, herbs; stipule ± scarious; (A 9), funicle long or short; n = 7 and up.

15/590: Polygonum (200+, if split, then Persicaria 150), Rumex (200), Calligonum (80). Especially (warm) temperate.

Synonymy: Calligonaceae Chalkuziew, Persicariaceae T. Post & Kuntze, Rumicaceae Martynov

2. Eriogonoideae Arnott

Woody and lianescent, with stem tendrils [?plesiomorphic], or trees (herbs); (plant dioecious); (inflorescence ± cymose, with involucre - Eriogonum et al.).

28/520: Eriogonum (250, but paraphyletic), Coccoloba (120). Largely tropical, America and the Antilles (West Africa), Eriogonum and relatives esp. W. North America.

Synonymy: Eriogonaceae G. Don

• The flowers of Polygonaceae are rather small, all parts (bar the carpels) are more or less free, and the 5 or 6 tepals are persistent or enlarged in fruit; the achene itself is often angled. A sheathing stipule is common and the nodes of the herbaceous taxa in particular are more or less swollen. Eriogonum and relatives lack the distinctive stipule and have a more or less cymose and involucrate inflorescence.

Evolution. Lycaeana and Heliophorus (Lycaenini) are found on this family throughout its extratropical range (Ehrlich & Raven 1964). Eriogonum and relatives are very diverse in the drier regions of southwest North America (and some apecies also in southern South America), and may represent a relatively recent radiation (Sanchez & Kron 2008).

Interestingly, in view of the general paucity of mycorrhizae in Caryophyllales, endomycorrhizae are reported from Eriogonum and ectomycorrhizae from Coccoloba (Malloch et al. 1980).

Chemistry, Morphology, etc. Williams et al. (1994) noted that although no plumbagin had been reported from the family, other quinones were known there. Sieve tube plastids with protein fibers are reported from Triplarieae (Behnke 1999). The climber Antigonon has leaf tendrils and successive cambia. There are often subepidermal strands of collenchyma or sclerenchyma in the stem in Polygonaceae (see also Plumbaginaceae). It has been thought that the flowers of Polygonaceae are basically 3-merous; the carpels are opposite the outer perianth whorl when the perianth is 3 + 3. Flowers with five tepals would then be derived from those with six, perhaps by fusion of two of the members. Recent work, however, suggests that the basic condition for the family is to have five tepals (Lamb Frye & Kron 2003; Burke et al. 2009). Some species of Rumex have an X-autosome balance system determining the 'sex' of the plant. Stamens in Fagopyrum are both introrse and extrorse (Le Maout & Decaisne 1868). The exact nature of the funicle is unclear; it might be a reduced basal placenta.

For more information, see Hegnauer (1969, 1990: chemistry), Haraldson (1978: general), Brandbyge (1993: general), Carlquist (2003a: wood anatomy) and Logacheva et al. (2008: especially expansion of the inverted repeat). I thank Adriana Sanchez for comments.

Phylogeny. The largely herbaceous Eriogonoideae s. str., i.e. Eriogonum and its immediate relatives, used to be kept separate from the rest of the family, placed in Polygonoideae, and of variable habit, because the former lacked a sheathing stipule, their inflorescence was cymose and with an involucre, while the latter had a sheathing stipule and a racemose inflorescence that lacked an involucre. However, studies show a different division of the family into two moderately supported clades, largely woody and largely herbaceous respectively. The former includes Eriogonoideae s. str., and these are derived from within this woody clade, the woody Coccolobeae appear to be paraphyletic (e.g. Cuénoud et al. 2002; Lamb Frye & Kron 2003); [Antigonon + Brunnichia], both lianes, are sister to the rest of the woody clade (Sanchez & Kron 2008), or perhaps Symmeria and Afrobrunnichia (position of latter not so clear) are below the [Antigonon + Brunnichia] clade (Sanchez et al. 2009a; Sanchez & Kron 2009; see also Burke et al. 2009). Indeed, Sanchez et al. (2009b) found that Afrobrunnichia was sister to Eriogonoideae and Symmeria sister to the whole of the rest of the family using chloroplast data, Afrobrunnichia was sister to Polygonoideae and Symmeria sister to Eriogonoideae using ITS data, while in a combined analysis the relationships were [Symmeria [Afrobrunnichia + rest of family]] - of course, not all support values were high... Eriogonum itself is paraphyletic and includes taxa like Chorizanthe and Dedeckera (Sanchez & Kron 2006, 2008). Polygonoideae s. str. are more or less herbaceous. Generic limits around Polygonum are difficult, and the genus has sometimes been split (e.g. Brandbyge 1993; Kim & Donoghue 2008; Kim et al. 2008). The mostly viney Muehlenbeckia (nestled in Fallopia) is also to be included in Polygonoideae (Schuster & Kron 2008).

Rhabdodendraceae [Simmondsiaceae [[Asteropeiaceae + Physenaceae] [Caryophyllaceae, Nyctaginaceae, Cactaceae, etc.]]: styles stigmatic their entire length; endosperm slight.

Evolution. This clade may have diverged from the [Droseraceae group [Tamaricaceae group + Polygonaceae group]] clade 82-76 million years before present, but diversification of the core Caryophyllales did not occur until substantially later at 47-39 million years before present (Wikström et al. 2001).

Chemistry, Morphology, etc. The morphology, etc., of the basal members of this clade, poorly known though they are, seem rather different from those of the core members.

RHABDODENDRACEAE Prance   Back to Caryophyllales

Woody; ellagic acid +; cork?; (successive cambia 0); dark-staining deposits esp. in rays; nodes multilacunar; sieve tube plastids with protein crystalloids and starch; secretory cavities with resin; foliar fibre-like sclereids +; hairs peltate, cells with SiO₂ bodies; leaves revolute, obscurely punctate; inflorescence axillary, branched, ?with terminal flower; hypanthium +, short, K short, ± connate, C rather thick; A many, filaments very short, anthers very long, exodermis tanniniferous, nectary?; G 1, with 1 (2) basal campylotropous ovules, bitegmic zone short, nucellar cap 0, archesporium multicellular, stylulus basal, stigma much elongated, ?type; fruit a drupelet, surrounded by K, pedicel swollen; exotestal cells tangentially elongated, underlying cells short-tracheidal; endosperm type?, 0, embryo green, curved, with large cotyledons; n = 10.

1[list]/3. Tropical South America (map: see Prance 1972c). [Photo - Flower]

• Rhabdodendraceae are evergreen trees that may be recognised by their fringed-peltate hairs, their rather large, entire and exstipulate leaves, flowers with stamens that have short filaments and long anthers, and a single carpel with a basal style. The fruit is distinctive, the drupes being surrounded by the persistent calyx and swollen pedicel apex. The punctations in the lamina may not be at all obvious.

Chemistry, Morphology, etc. I have not seen stipules (cf. Prance 1972c), but the rather broad petiole base can be confused with them. The ovule is often described as being unitegmic (e.g. Nandi et al. 1998, following Puff & Weber 1976; but see Tobe & Raven 1989); check the micropyle. The styluli may be stigmatic for only part of their lengths. The embryo is surrounded largely by testa that develops from the unitegmic part of the ovule.

For general information, see Prance (2002).

Previous relationships. The position of Rhabdodendraceae has long been uncertain. Thus they were placed in Rutales by Takhtajan (1997), although Prance (1968) had much earlier suggested a position in this general area.

Simmondsiaceae [[Asteropeiaceae + Physenaceae] [Caryophyllaceae, Nyctaginaceae, Cactaceae, etc.]]: nodes 1:1; C 0.

SIMMONDSIACEAE van Tieghem   Back to Caryophyllales

Evergreen shrubs; ellagic acid 0; cork pericyclic; true tracheids +; stomata cyclocytic and laterocytic; hairs uniseriate; leaves opposite, articulated near stem, flat, 2ndary veins ascending from near base; plant dioecious; flowers small, (4, 6-merous); P +; nectary 0; staminate plant: inflorescence usu. terminal, cymose; A 2x P, extrorse, anthers basifixed, longer than connective, pollen ± porate, central part operculoid, spinules minute; carpellate plant: flowers axillary; G [3], 1 apical pendulous apotropous ovule/carpel, outer integument ca 10 cells and inner integument 4-5 cells thick, styles papillate all around; fruit a capsule, K accrescent, columella persistent; seed 1, testa multiplicative, vascularised, exotestal cells palisade, walls thickened, mesotesta aerenchymatous, rest collapsed; endosperm reserve?; n = 13.

1[list]/1: Simmondsia chinensis (!: note the epithet). S.W. North America, the Sonoran Desert (map: see Sherbrooke & Haase 1974). [Photos - Collection]

• Simmondsiaceae are evergreen shrubs that may be recognised by their opposite leaves that are clearly articulated near the stem and have flat, rather thick blades with entire margins. The staminate flowers are small and borne in terminal inflorescences while the carpellate flowers are single and axillary; the calyx is much enlarged in fruit.

Chemistry, Morphology, etc. The large embryo contains liquid wax made up of esters of high molecular weight, mono-ethylenic acids. The stamens are described as being latrorse (Takhtajan 1997).

For general information, see Mathou (1939), for chemistry, see Hegnauer (1989, as Buxaceae), for testa anatomy, etc., see Tobe et al. (1992), for general information, see Köhler (2002), and for wood anatomy, see Carlquist (2002b).

Previous Relationships. Simmondsiaceae have usually been included in Buxaceae or placed in a separate family, but close to Buxaceae; Simmondsiales are included in Hamamelididae (Takhtajan 1997).

[[Asteropeiaceae + Physenaceae] [Caryophyllaceae, Nyctaginaceae, Cactaceae, etc.]]: ?

[Asteropeiaceae + Physenaceae]: successive cambia 0; young stem with vascular cylinder; wood parenchyma aliform-confluent; vasicentric tracheids +, fiber tracheids +; rays 1-2 cells wide; A latrorse; fruit single-seeded.

Some information on the general anatomy of these two families is taken from Harms (1893); Carlquist (2006) compares their wood anatomy.

ASTEROPEIACEAE Reveal & Hoogland   Back to Caryophyllales

Evergreen trees or scrambling shrubs; ellagic acid?; pericyclic fibers +; petiole bundle annular; epidermal mesophyll sclereids +; ?stomata; inflorescence terminal, branched, pedicels with many bracteoles; C +, deciduous; A 9-15, basally connate, (pollen 6-rugate); G [(2) 3], 2-many ± apical ovules/carpel, ?micropyle, (style short, stigma lobed), stigma continuous across G; fruit nutlike, (several-seeded), K accrescent and forming wing; A persistent; seed coat?; endosperm reserve?, embryo curved, cotyledons spirally coiled; n = ?

1[list]/8. Madagascar. [Photos - Collection]

• Asteropeiaceae are evergreen trees that may be recognised by their shortly petiolate leaves whose blades are entire, exstipulate and have rather indistinct venation. The flowers are small are in terminal panicles, the fruit has a single seed, and the calyx is much accrescent and spreading.

Evolution. Asteropeia is ectomycorrhizal (Ducousso et al. 2008).

Chemistry, Morphology, etc. Some information is taken from Beauvisage (1920: anatomy), Miller (1975: wood anatomy), Morton et al. (1997b: general), Schatz et al. (1999: revision), and Kubitzki (2002d: general).

Previous Relationships. Asteropeiaceae were previously often included in Theaceae or Theales (Cronquist 1981; Takhtajan 1997), but are very different in wood anatomy (Baretta-Kuipers 1976); the rays are uniseriate.

PHYSENACEAE Takhtajan   Back to Caryophyllales

Shrub or tree; triterpene glycosides, oxohexadecanoic acid [keto fatty acid] +; ellagic acid?; pericyclic sclereids +; cuticle wax crystalloids?; ?petiole bundle; leaves two-ranked; plant dioecious; inflorescence axillary, racemose; P 5-9, staminate flowers: A (8-)10-14(-25), basifixed, anthers long; carpellate flowers: G [2], septae incomplete, 2 ± subbasal campylotropous ovules/carpel, funicle long; fruit subdrupaceous?; seed large, coat vascularised, 16-20 layers thick, walls not notably thickened; endosperm 0, reserve?, cotyledons unequal; n = ?

1[list]/2. Madagascar. [Photos - Collection]

• Physenaceae are rather undistinguished with their more or less two-ranked, entire, exstipulate and coriaceous leaves. The flowers lack a corolla, the stamens have a very thin filaments and long anthers, and the styles are long. The fruit is inflated and contains a single seed which apparently has a vascularised seed coat.

Chemistry, Morphology, etc. The petiole is often described as being articulated; it commonly breaks transversely above the base. The leaf bundles are completely surrounded by mechanical tissue. There are brachysclereids in the secondary phloem and the placental bundles are inverted (Dickison & Miller 1993).

General information is taken from Morton et al. (1997b) and Dickison (2002); for triterpene glycosides, see Inoue et al. (2009).

Previous Relationships. Physenaceae were included in Urticales by Cronquist (1981) and placed in a monotypic Physenales in Dilleniidae by Takhtajan (1997).

[Caryophyllaceae, Nyctaginaceae, Cactaceae, etc.]: Plant herbaceous; CAM [especially pervasive in succulents] and C₄ photosynthesis common; ferulic acid ester-linked to primary unlignified cell walls; (O-methylated) flavonols, quinones, betalains [chromoalkaloids], triterpenoid saponins +, tannins, myricetin 0; (phytoferritin +); sieve tube plastids with a ring of proteinaceous filaments and a central angular crystalloid (also with starch); pericyclic fibers 0 [phloem-derived fibers quite widespread]; (mucilage cells +); (stomatal orientation transverse); inflorescence cymose; (stamens equal and opposite perianth members), pollen trinucleate, (polyaperturate), foot layer thin, nectaries on adaxial bases of stamens, placentation free central or basal; G with median member adaxial, ovules campylotropous, (funicles long), stigmas papillate, little expanded; seeds with exotestal and endotegmic cells thickened, (space between testa and tegmen), bar-like thickenings on endotegmic cells; endosperm 0, perisperm +, starch grains clustered, embryo curved; mitochondrial rps 10 gene and chloroplast rpl2 [latter present in some Portulaca?] gene intron lost.

Evolution. Core Caryophyllales contain ca 5.3% of eudicot diversity (Magallón et al. 1999). Fossils identified as Amaranthaceae are dated to the Santonian/Campanian, ca 83 million years before present (Magallón et al. 1999), but molecular estimates of the age of the clade are only some 28-40 million years before present (Wikström et al. 2001) - something is clearly wrong.

Taxa growing in saline and/or dry conditions are noticeably well represented here, and taxa that can grow on gypsum (hydrous calcium sulphate) are scattered throughout the clade (Douglas & Manos 2007). Succulents are common, and many taxa have C₄ photosynthesis or CAM or their variants. Core Caryophyllales are little liked by butterfly caterpillars (Ehrlich & Raven 1964).

The course of evolution of betalains and anomalous secondary thickening in this group has long been uncertain, but it now seems unlikely that the presence of anthocyanins is plesiomorphic (Cuénoud et al. 2002; Cuénoud 2002a; see also Clement & Mabry 1996), and normal secondary thickening may also be apomorphic. Perianth differentiation also shows a complex pattern of evolution, occuring maybe nine time or so in the clade and in a variety of ways (Brockington et al. 2009).

Chemistry, Morphology, etc. Sterol composition may be of systematic interest (Wolfe et al. 1989; Patterson & Xu 1990), with distinctive sterols common or dominant in Caryophyllaceae, Phytolaccaceae, Amaranthaceae, and "Portulacaceae"; isoflavonoids (Reynaud et al. 2005) and phytoecdysones are scattered, but perhaps not in the Cactaceae area, and the former are sometimes quite diverse. Stomatal morphology is variable, but anomocytic stomata are common in all families. However, in Cactaceae and relatives, parallelocytic and other kinds of stomata are found; some families in this area have predominantly paracytic stomata. Stomatal orientation on stem and/or leaf is commonly transverse apparently throughout the order (Butterfass 1987, ?Amaranthaceae s. str.?), however, it is unlear which taxa have vertically or which unoriented stomata. Variation in structures associated with the leaf base, whether hairs or "stipules", is considerable (Rutishauser 1981) and would repay further study; note that the basic nodal anatomy of the clade is one trace-one gap, unusual for plants with stipules as commonly accepted.

Any "corolla" present, as in Caryophyllaceae, is usually described as being of staminal origin (e.g. Ronse Decraene & Smets 1993; Leins et al. 2001). It arises at the same time or after the androecium, not before it, and the "petals" and stamen(s) opposite them may form a developmental unit (e.g. Eichler 1875; Wagner & Harris 2000). The corona - in Lychnis viscaria, at least - arises from two bulges on the adaxial side of the "corolla", perhaps representing anther thecae. When the stamens are equal in number to the perianth members they are opposite to them, when there are many stamens the initial primordia either alternate with them (Aizoaceae), or continue the spiral of the tepals (Pereskia - Cactaceae: see Leins & Erbar 1994); development is centrifugal. Carpels are quite commonly open in development - also in Polygonaceae (Tucker & Kantz 2001). Placentation is quite variable, although one commonly thinks of this group as being free central of its variants; the basal condition for the clade may indeed be free-central. There may be a subepidermal layer of cells in the ovary with conspicuous calcium oxalate deposits, as in some Amaranthaceae and Polygonaceae(!), although in Nyctaginaceae, for example, cells immediately below the ovary have conspicuous raphide deposits (Guéguen 1901); there is little information on this feature. The apical cells of the nucellus are commonly elongated radially (e.g. in Cactaceae, "Portulacaceae", Aizoaceae, Phytolaccaceae, and Amaranthaceae: see Johri et al. 1992), i.e., they form a nucellar pad, but it is unclear if this is a feature of systematic significance; Naryana (1962: e.g. Aizoaceae, Gisekiaceae, Molluginaceae) draws cells over the apex of the embryo sac as occuring in radial files, i.e., they seem to form a nucellar cap. There are often short hairs on the funicle that are directed towards the micropyle (Neumann 1935). Seeds of a number of taxa have an operculum, although not necessarily identical in morphology (Bittrich & Ihlenfeldt 1984). Finally, there are commonly bar-like thickenings on the walls of the endotegmic cells (e.g. Netolitsky 1926; Bittrich 1993; perhaps shown in Narayana 1962), although these are absent from most Caryophyllaceae, at least - a complete survey would be useful. For the loss of the intron of the rpl2 gene, see Logacheva et al. (2008).

Additional information is taken from Zandonella (1977: nectaries), Rutishauser (1981: "stipules" and similar structures), Hegnauer (1989: general chemistry), Wolfe et al. (1989: sterols), Patterson & Zu (1990: sterols), Steglich and Strack (1990: betalains), Barthlott (1994: waxes), Behnke (1994a: sieve tube plastids, phytoferritin), Gibson (1994: stem anatomy), Hofmann (1994: floral morphology), Nowicke (1994: pollen), Werker (1997: seed coat), Jansen et al. (2000c: successive cambia), Cuénoud (2006: summary) and Sage et al. (1999) and Muhaidat et al. (2007 and references) for the C₄ pathway.

Phylogeny. Achatocarpaceae + Amaranthaceae + Caryophyllaceae were found to form a moderately well supported clade, the rest of the core Caryophyllales another (Källersjö et al. 1998), however, although 13 families were included in this study, sampling within them was poor. Similar relationships were suggested by Savolainen et al. (2000a). D. Soltis et al. (2000) found that Phytolaccaceae, Nyctaginaceae and Delosperma (Aizoaceae) formed a group, also Amaranthaceae plus Caryophyllaceae, but again the sampling was very sparse. For the position of Achatocarpaceae, see also Müller and Borsch (2005). For other suggestions of relationships, see Rodman (1994) and Downie and Palmer (1994: structural variation in chloroplast DNA). The particular relationships in the tree here are largely those suggested by Cuénoud et al. (2002: note, they excluded the Delosperma sequence), and these are largely similar to relationships found by Källersjö et al. (1998) and other workers, albeit the sampling is much more detailed. Cuénoud et al. (2002) found two quite well supported clades within core Caryophyllales (see tree), but sampling still needs to be improved. Along with others, Cuénoud et al. (2002) found Aizoaceae to be monophyletic, albeit with only slightly better than marginal (52% bootstrap) support in an analysis of matK sequences, the only gene for which they had moderately good sampling. Gisekia moved position in analyses of rbcL and matK sequences (cf. Cuénoud et al. 2002), and Sarcobatus was sister to Nyctaginaceae, albeit with only weak support, in matK analyses, while in a rbcL analysis it grouped with Agdestis (cf. Cuénoud et al. 2002). Relationships around Cactaceae, themselves a monophyletic group, still remain difficult, although progress has recently been made here, too (see also below). Nevertheless, more work is needed to clarify relationships within core Caryophyllales. In general, morphological distinctions between the clades are slight. It is rather curious that Harbaugh et al. (2009) found that Molluginaceae were sister to Caryophyllaceae, rather than Amaranthaceae, although two taxa from both families were all that were included in their study, which focused on Caryophyllaceae.

Previous Relationships. Most of this group was included in the old Centrospermae (so named because of the basal or free-central placentation that is common in the clade) or Caryophyllales in the strict sense. The shikimic acid pathway, particularly phenyalanine, is a starting point for the synthesis of nitrogen-containing benzylisoquinoline alkaloids and the betalains of core Caryophyllales; Kubitzki (1994) suggested a relationship between core Caryophyllales, Magnoliidae and monocots because all contained such compounds.

Caryophyllaceae [Achatocarpaceae + Amaranthaceae]: (phytoecdysteroids +); esp. outer wall of exotesta thickened and with stalactite-like projections; mitochondrial rps1 and 19 genes lost.

Chemistry, Morphology, etc. The status of the characters above in Achatocarpaceae is unknown. For phytoecdysteroids, see Báthori et al. (1987), Dinan et al. (1998), and Zibareva et al. (2003). Mickesell (1990) listed both Amaranthaceae and Caryophyllaceae as having endosperm haustoria. Sukhorukov (2007) described the exotegmic cells of Chenopodiaceae s. str. as often having tannin deposits in the outer walls of the exotegmic cells that projected into the cell lumen.

CARYOPHYLLACEAE Jussieu, nom. cons.   Back to Caryophyllales

Herbs (shrubs, lianes); cyclopeptides, anthocyanins, glycoflavones, anthraquinones +; cork usu. pericyclic; true tracheids, fibers +; pericyclic fibers +; nodes often swollen; stomata often diacytic; (cuticle waxes as rodlets); leaves conduplicate or ± flat; (plant dioecious); flowers 4-5-merous; A (1-) 5, 10 (obdiplostemonous; 15), outer secondary parietal cell dividing, (pollen 6(+) porate; nectary on receptacle); G [2-5], also opposite "C", (1 basal-)many ovules/carpel, placentation often axile basally when young; nucellar cap +, funicle?; styles impressed [distribution?]; fruit a septicidal and loculicidal capsule (circumscissile); (endotesta thickened; endotegmen ± thickened); embryogeny solanad, initially distinct air space between the cotyledons [?all taxa]; n = 7--15, 17; protein bodies in nuclei; mitochondrial coxII.i3 intron 0; sporophytic self-incompatibility system present.

86[list]/2200 - 11 groups below. Mostly temperate, esp. Eurasian (map: from Vester 1940; Hultén 1971). [Photos - Collection, Minuartia Habit,Microphyes Flower]

1. Corrigioleae Dumortier

Stipules scarious, auriculate; hypanthium +; K with scarious margins; G with incomplete septae; endotegmic cells lacking bar-like thickenings.

2/16. Mediterranean to Pakistan, Africa, Chile; Corrigiola litoralis widely distributed.

Synonymy: Corrigiolaceae Dumortier, Telephiaceae Martynov

Paronychieae [Polycarpeae [Sperguleae [[Sclerantheae + Sagineae] [[Arenarieae + Alsineae] [[Sileneae [Caryophylleae + Eremogeneae]]]]]]: leaves opposite.

2. Paronychieae Dumortier

Stipules scarious, + [paired, subadaxial to petiole; paired, connate, adaxial; single, concave, adaxial or interpetiolar]; hypanthium ± +; K hooded, subapically awned, (with scarious margins), C filiform, (0); fruit a nut, 1-seeded.

15/190: Paronychia (110), Herniaria (45). Worldwide, esp. Paronychia, diverse in genera Mediterranean to Middle East.

Synonymy: Herniariaceae Martynov, Illecebraceae R. Brown, nom. cons., Paronychiaceae Jussieu

Polycarpeae [Sperguleae [[Sclerantheae + Sagineae] [[Arenarieae + Alsineae] [[Sileneae [Caryophylleae + Eremogeneae]]]]]: ?

3. Polycarpaeae de Candolle

Stipules + [interpetiolar fimbrieae, from common primordium]; hypanthium ± +; K usu. hooded, awned, (with scarious margins), C deeply lobed to entire or 0; styles basally connate.

Polycarpaea (50), Drymaria (48). Almost worldwide.

Synonymy: Ortegaceae Martynov, Polycarpaeaceae Schur

Sperguleae [[Sclerantheae + Sagineae] [[Arenarieae + Alsineae] [[Sileneae [Caryophylleae + Eremogeneae]]]]: ?

4. Sperguleae Dumortier

Stipules scarious [single, interpetiolar, connate and encircling stem below leaves]; hypanthium inconspicuous; K with scarious margin.

Synonymy: Spergulaceae Adanson

[Sclerantheae + Sagineae] [[Arenarieae + Alsineae] [[Sileneae [Caryophylleae + Eremogeneae]]]: stipules 0

Sclerantheae + Sagineae:

5. Sclerantheae de Candolle

Hypanthium +/0; (K with membranous margins); (C 0); A 1-10, (5 staminodes); (fruit a nut, 1-seeded).

Northern Hemisphere, Australasia, Ethiopia.

Synonymy: Scleranthaceae Berchtold & J. S. Presl

6. Sagineae Tanf.

Hypanthium +/0; (K awned; with scarious margins); (A = C); (fruit a nut, 1-seeded).

Northern hemisphere, tropical montane, temperate southern hemisphere.

[Arenarieae + Alsineae] [Sileneae [Caryophylleae + Eremogeneae]]: hypanthium 0; capsule often with 2X teeth as styles; embryogeny caryophyllad.

[Arenarieae + Alsineae]:

7. Arenarieae Kitt.

(Oily funicular aril - Moehringia); cotyledons incumbent.

Arenaria (135). Northern hemisphere, Central and west South America.

Synonymy: Sarcocaceae Adanson

8. Alsineae Lamarck & de Candolle

(Hypanthium +); (K with scarious margins), C ± retuse; (fruit a nut, 1-seeded).

Stellaria (175), Cerastium (100), Odontostemma (38). North Hemisphere, esp. Eurasian, some cosmopolitan.

Synonymy: Alsinaceae Bartling, nom. cons., Cerastiaceae Vest, Stellariaceae Dumortier

[Sileneae [Caryophylleae + Eremogeneae]]: veins at apex of lamina intramarginal; hypanthium 0; K ± connate; (anthophore [prolongation between K and the rest of the flower] +); C clawed, contorted, apex retuse or not, venation closed, coronal scale +/0.

9. Sileneae de Candolle

K with commissural veins, C variously contorted (imbricate); (placentation axile basally).

?6/738: Silene (700). North Temperate, African montane.

Synonymy: Lychnidaceae Lilja, Ortegaceae Martynov, Silenaceae Bartling

[Caryophylleae + Eremogeneae]: ?

10. Caryophylleae Lamarck & de Candolle

("Epicalyx" +); K without commissural veins; C dextrose-contorted (imbricate); G 2 (3); n = 12-15, 16.

17/610: Dianthus (300), Gypsophila (150), Acanthophyllum (75). Eurasia (Africa, Gypsophila australis Australia and New Zealand).

Synonymy: Dianthaceae Vest

11. Eremogoneae Rabeler & W. L. Wagner

Leaves linear, ± rosette-forming; hypanthium poorly (well) developed; K with scarious margins, hardened at base; cotyledons accumbent.

2/68: Eremegonum (66). (Eur)Asian, west North America.

• Caryophyllaceae can be recognised by their herbaceous habit, opposite, entire leaves that often have little in the way of a petiole and are joined by a line at the base; geotropic adjustments occur at the swollen nodes. The inflorescence is cymose and the flowers appear to have a clearly distinguishable calyx and corolla, the latter being bilobed and/or clawed; there are usually 5 or 10 stamens. The fruit is a capsule. Note, however, that the calyx in Caryophyllaceae can be very scarious, as in Brachystelma, while herbaceous Amaranthaceae also often have swollen nodes (and opposite leaves)...

Evolution. The earliest fossils linked to Caryophyllaceae seem to be of the pollen Periporopollenites polyoratus, from the Late Campanian ca 73 milion years ago. This has been linked with the macrofssil Caryophylliflora paleogenica from the Eocene of Tasmania, but these fossils cannot be placed with any known member of the family (Jordan & McPhail 2003).

Silene and its relatives may be pollinated by moths which at the same time lay eggs on the ovary, rather like the yucca - moth association (Kephart et al. 2006 for literature, also other papers in that issue of the New Phytologist [169(4)]).

Relatives of Schiedia, which forms a substantial radiation on Hawaii, appear to be the likes of Honckenya, Arctic and subarctic (Harbaugh et al. 2009).

Ectomycorrhizae have been reported from the family (Wang & Qiu 2006). For anther smut fungi, see Ngugi and Scherm (2006). Microbotryium violaceum s.l. is common on the family, although perhaps not on the old Paronychioideae, and not much on perennial Silene, more on annuals; strict cospeciation is not involved (Refrégier et al. 2008; Mena-Ali et al. 2009).

Chemistry, Morphology, etc. Variation in stipule morphology in Caryophyllaceae is considerable, even during the course of development of a single plant, as in Paronychia argentea ((Rutishauser 1981). The long, curved nectary in Schiedia develops on the abaxial bases of the stamens alternating with the calyx (Wagner & Harris 2000), i.e., it is probably similar to the petals in other taxa. Weberling (1989 and references) discusses the placentation of the family, which varies from axile (as in some species of Silene) to free central to the single, basal ovule of Uebelinia; the latter condition approaches a circinotropous basal ovule. Members of the old Paronychioideae have solanad rather than caryophyllad embryo development. Some species of Silene have an X-Y 'sex' determination system.

Some general information is taken from Bittrich (1993); for information on the old Alsinoideae - and a number of maps - see McNeill (1962), for stomata, see Rohweder et al. (1971: correlation between stomatal apparatus and leaf width), for stem anatomy, see Schweingruber (2007), general chemistry, see Hegnauer (1964, 1989), for the distribution of phytoecdyosteroids, see Zibareva et al. (2003), and of cyclopeptides, see Jia et al. (2004).

Phylogeny. Of the old sabfamilies, Paronychioideae - classically defined by the presence of stipules, lack of a corolla, and utricular fruit - are a basal grade, with Corrigioleae (Telephium, Corrigola) sister to the rest of the family. Dicheranthus, Polycarpon, etc., may form the next clade, Paronychia, etc., the next. Drymaria and Pycnophyllum, both morphologically distinctive taxa, may be sister (Smissen et al. 2002 - they noted that Pycnophyllum [and Pentastemonodiscus] were not to be included in Caryophyllaceae-Alsinoideae, but they did not suggest where they should go; Fior et al. 2006). In the erstwhile Alsinoideae the calyx is free and the corolla has ± open venation. Alsinoideae for the most part break down into two groups: one, including Cerastium, Stellaria, etc., has capsules with split valves, and the other including Minuartia, etc., is very diverse, but has capsules with entire valves; the corolla is often bilobed. For Moehringia, the evolution of its strophiole, and its allies, see Fior and Karis (2007 and references). Finally, Caryophylloideae, with their connate calyx and a clawed corolla with more or less closed venation and adaxial appendages (ligules), are holding up better phylogenetically. The tribes Sileneae and Caryophylleae are perhaps monophyletic, and together are sister to or form a polychotomy with part of Arenaria (Nepokroeff et al. 2002; Fior et al. 2006); for Silene and its relatives, perhaps not monophyletic, see Desfeux and Lejeune (1996) and Erixon and Oxelman (2008), for Viscaria, etc., Frajman et al. (2009).

Recent studies have clarified the picture. Relationships - on the whole well supported - from a three-gene analysis being [Corrigolieae [Paronychieae [Polycarpeae [Sperguleae [[Sclerantheae + Sagineae] [[Arenarieae + Alsineae] [Sileneae [Caryophylleae + Eremogeneae]]]]]]]] (Harbaugh et al. 2009). However, the position of the newly described Eremegoneae is uncertain; in its current position either it should have as additional apomorphies the apomorphies of the whole [Sileneae [Caryophylleae + Eremogeneae]] clade, but as losses, or these features should arise independently in Sileneae and Caryophylleae. The phylogenetic structure of the family as a whole has considerable implications for character evolution in it.

Classification. The old tripartite division of the family into Silenoideae, Alsinoideae and Paronychioideae based on presence of a hypanthium, whether or not the petals were emarginate, whether the calyx was fused or not, etc., is not confirmed by any recent work (e.g. Nepokroeff et al. 2002; Smissen at al. 2002; Fior et al. 2006). Here I follow the tribal classification of Harbaugh et al. (2009), although as these authors note a number of genera are unsampled, so both the number and also the generic composition of some tribes is uncertain. Thus if Drypis, currently in Caryophylloideae and with a connate calyx, etc., is in the same immediate clade as Habrosia, currently in Alsinoideae, the variation within the Sagineae as circumscribed by Harbaugh et al. (2009) will be very considerable.

Features like number of styles and whether the styles are free or there is obviously a common stylar region have provided generic characters in the past. However, the limits of Silene, historically characterised by having three styles, need to be exapanded to include some taxa with five styles (Desfeux & Lejeune 1996), and genera like Arenaria and Minuartia are polphyletic (Harbaugh et al. 2009).

Achatocarpaceae + Amaranthaceae: pollen porate.

ACHATOCARPACEAE Heimerl, nom. cons.   Back to Caryophyllales

Woody; C-glycosylflavonoids +, betalains?; cork?; secondary growth normal; nodes ?; cuticle waxes as ± lobed platelets in clusters; P 4-5; A 10-20, basally connate or not, pollen 6-porate; G [2], lateral or superposed, 1 (2) basal ovules, funicle?; fruit a 1-seeded berry; seeds with small aril; n = ?

3[list]/7. S.W. USA to South America (map: from Fl. N. Am. 4: 2003; GBIF 2008). [Photo © C.E. Hughes - Fruits, Fruiting branch].

Some information is taken from Bittrich (1993).

AMARANTHACEAE Jussieu, nom. cons.   Back to Caryophyllales

Succulent, herbaceous or shrubby (lianes), often in saline conditions; betaines, anthraquinones, (isoquiniline alkaloids), 6-7-methylene-dioxyflavonols, isoflavonoids +, soluble oxalate accumulation; often a few pericyclic fibers +; cork pericyclic [esp. chenopods] (and elsewhere); wood storied, rayless; crystal sand + [less common in chenopods], soluble calcium oxalate accumulation; cortical and/or medullary bundles + [less common in amaranths s. str.]; sieve tube plastids lacking protein crystalloid; nodes often swollen, (1:3, 1:5); petiole bundles ± annular; stomata also paracytic (dia- and anisocytic); hairs variable, often uniseriate, (adaxial to the leaf base - Anabasis); (leaves opposite), margins often toothed; (bracts and bracteoles scarious); P (1-)5(-8), ± herbaceous [chenopods] to scarious, stamens = P, joining disc (± connate; with appendages [pseudostaminodes]), (coloured vesicular anther appendages - Caroxyloneae), anther wall development monocotyledonous, (tapetum plasmodial), pollen multiporate, often starchy, foot layer well developed; G [1-3(-6)], (median member abaxial), with 1(-many) basal ovules, (chalazal region ± digested by the embryo sac), embryo sac haustorium +, style ± developed, stigmas capitate; fruit surrrounded by a persistent (subfleshy) perianth [anthocarp], bracts and bracteoles persistent and also often part of disseminule, or dry, circumscissile capsule or indehiscent, (berry; drupe); seed horizontal or not, endotegmen ± thickened and lignified, tanniniferous; (perisperm 0), embryo green or white (spiral - Salicornia etc.; straight); n = (6-)8, 9(-17).

174[list]/2050-2500: Chenopodium (100: C. quinoa), Atriplex (300), Gomphrena (120), Salsola (100), Alternanthera (100), Iresine (80), Amaranthus (60), Celosia (45). ± World-wide, esp. warm and dry temperate and subtropics, esp. saline habitats (map: from Hultén & Fries 1986; Jalas et al. 1999). [Photo - flowers, fruits, Collection.]

• Amaranthaceae are more or less succulent herbs often with swollen nodes; they prefer dry and/or saline habitats. The small flowers often have 1-3 carpels and 1-2 basal ovules. The fruits either have a circumscissile capsule and a chartaceous to scarious perianth and bracts or are indehiscent and are closely invested by the more or less fleshy perianth and bracts.

Evolution. Many taxa are halophytes (Jacobs 2001; Sage 2002), and in erstwhile members of Chenopodiaceae in particular the accrescent perianth may envelop the fruit, being variously winged or spiny (e.g. Cabrera et al. 2009). Although the family is apparently largely without mycorrhizae, vesicular-arbuscular mycorrhizae have been reported from chenopods in the Red Desert of Wyoming - but only on native taxa and under undisturbed conditions (Miller 1979).

There are several types of C₄ photosynthesis with ca 17 different kinds of leaf anatomy and probably 10+ independent acquistions of this photosynthetic pathway in Amaranthaceae (Kadereit et al. 2003; Sage et al. 2007); for details of the evolution of enzymes involved in Alternanthera, see Gowick et al. (2006). With some 800 species with C₄ photosynthesis, Amaranthaceae are by far the largest BLA group with this photosynthetic pathway. In at least three Suaedeae s.l. all the different elements of C₄ photosynthesis occur within a single cell, e.g. there is no conventional Kranz anatomy, but there is spatial segragation of the organelles involved in different parts of the carbon fixation process, and this has evolved independently at least twice (Kapralov et al. 2006); partitioning of the organelles within the cell is maintained by the distinctive organization of the cytoskeleton (Chuong et al. 2006), although there is plasticity induced by the light environment (Lara et al. 2008).

Chemistry, Morphology, etc. Amaranthaceae (inc. Chenopodiaceae) are palynologically fairly homogeneous (Nowicke 1975; Skvarla & Nowicke 1976), both having a similarly thickened tectum, apertures with reduced pointed flecks of exine underlain by lamellar plates, and a thickened endexine; Pseudoplantago has cuboid pollen. Müller and Borsch (2006c) discuss the evolution of the distinctive stellate pore ornamentation of some Amaranthaceae s. str. - there are several independent gains and losses.

Otherwise Amaranthaceae are morphologically heterogeneous. Some problem taxa: Pleuropetalum (leaves spiral; inflorescence racemose; P 5; A 8, connate basally; G 5-6, several basal ovules, fruit initially fleshy; n = 8, 9 - A paired in development [Ronse Decraene et al. 1999]), in Amaranthoideae (Townsend 1993); Microtea (leaves spiral; inflorescence racemose, flowers in groups of up to 3; A (2-)5-9, pollen pantoporate; G [2-4], orientation variable, unilocular, funicle quite long [Baillon 1886], styles diverging; fruit an achene. Phytolaccaceae-Microteoideae Nowicke. 2/13. Central and South America, Antilles; S. Africa [Urban 1885], and with Lophiocarpus (Rohwer 1993) in Phytolaccaceae - Lophiocarpaceae Doweld & Reveal.

For a discussion about the cortical vascular system, see Beck et al. (1982). Stem collenchyma is well developed; there are nucleated xylem fibers (Rajput 2002). 2-carpellate members of the family usually have transverse carpels, but occasionally they are median. The chalazal region of the ovule is more or less digested by the embryo sac in at least some Amaranthaceae - and this is also once recorded from Nyctaginaceae (Maheshwari 1950).

Additional information is taken from Hegnauer (1964, 1989: chemistry), Blunden et al. (1999: betaine distribution, very common and widespread), Robertson (1981: general), Kühn (1993), Townsend (1993: general), Judd and Ferguson (1999: general), Rajput (2002: anatomy), Carlquist (2003c: anatomy), Shepherd et al. (2005b; seed anatomy), and Sukhorukov (2007, 2008: fruit wall anatomy); Flores Olvera et al. (2006) and Tsymbalyuk (2008) provide information on pollen.

Phylogeny. Amaranthus (Amaranthoideae: anthers 4-locellate at maturity, dehisce by 2 slits; 1-many ovules) is sister to Beta, etc., in ORF 2280 phylogenies, and this whole group is in turn sister to Celosia [Celosieae (monophyletic, several ovules, derived) and Froelichia, etc. + Gomphreneae/Gomphrenoideae which together have a connate androecium (and very scarious perianth and bracts). Amarantheae are polyphyletic. Cuénoud et al. (2002) found Amaranthaceae s. str. to be monophyletic, with very strong (97%) support, and Chenopodiaceae s. str. were perhaps monophyletic, but the branch collapsed in a strict consensus tree; the sampling was moderately good, but only one gene - matK - was analysed. In an extensive rbcL analysis, much of the old Chenopodiaceae were monophyletic, but with little bootstrap support, ditto the old Amaranthaceae (incl. Polycnemoideae), while Betoideae were paraphyletic (G. Kadereit et al. 2003). Other studies suggest paraphyly of Chenopodiaceae and sometimes even potential polyphyly of Amaranthaceae (Pratt 2003; Pratt et al. 2001). In an analysis of matK/trnK sequences, Müller and Borsch (2005b; see also Müller & Borsch 2005c), Polycnemum and Nitrophila (100% support) were sister to the rest; they have ordinary secondary thickening, imperfect flowers, basally connate filaments, and unithecate anthers. The rest of the Amaranthaceae + Chenopodiaceae had <70% support (and still lower posterior probabilities), while the Amaranthaceae s. str. had 100% support and the Chenopodiaceae s. str. again <70% support, but this time 100% posterior probabilities.

Within Amaranthaceae s. str. - at least some flowers imperfect - Bosea and Charpentiera were successively sister to the rest, but Amaranthoideae and Amarantheae were paraphyletic. Gomphrenoideae are monophyletic, and have monothecal anthers and metareticulate pollen, the mesocolpium being raised (see Downie et al. 1997). Within Gomphrenoideae are the iresinoids and the gomphrenoids (Gomphrena is polyphyletic) + althernanthoids (Alternanthera is monophyletic) (Sánchez del-Pino et al. 2009). Some of the extreme halophytic genera are morphologically much modified, and generic limits are difficult; in the reduced perianth of the Australian Tecticornia (Salicornioideae) the odd member is abaxial (Shepherd et al. 2004, 2005a, esp. Shepherd & Wilson 2007, also nomenclatural changes). Cabrera found generic problems in the Australian Camphorosmeae, Maireana being in a particular mess. See also Schütze et al. (2003), G. Kadereit et al. (2005: Australian chenopods, 2006: Salicornioideae) and Akhani et al. (2007: Old World Salsoleae [Salsoloideae - mostly C₄, embryo spiral, perisperm ± 0; seed compressed]) for studies on groups of Chenopodiaceae sensu stricto.

Amaranthaceae sensu stricto have cuticle waxes lacking platelets; scarious bracts and perianth, and the filaments are often connate; n = (6-)8-9(-13, etc). The embryogeny is chenopodiad[!]. Chenopodiaceae sensu stricto quite commonly have isoflavonoids; cuticle waxes as platelets; bracts and P ± fleshy, pink to red; fruit rarely circumscissile; n = 9; 300 bp deletion in chloroplast DNA inverted repeat.

Synonymy (A = Amaranthaceae s. str., C = Chenopodiaceae s. str.): Achyranthaceae Rafinesque (A), Atriplicaceae Durande (C), Betaceae Burnett (C), Blitaceae T. Post & Kuntze (C), Celosiaceae Martynov (A), Chenopodiaceae Ventenat, nom. cons., Corispermaceae Link (C), Deeringiaceae J. Agardh (A), Dysphaniaceae Pax, nom. cons. (C: cuticle waxes absent), Gomphrenaceae Rafinesque, Polycnemaceae Menge (C), Salicorniaceae Martynov (C), Salsolaceae Menge (C), Spinaciaceae Menge (C)

Stegnospermataceae [Limeaceae [Lophiocarpaceae [Aizoaceae, Nyctaginaceae, etc.]] [Molluginaceae, Cactaceae, etc.]]: ?

STEGNOSPERMATACEAE Nakai   Back to Caryophyllales

Woody, ± scandent; plant glabrous; true tracheids +; leaves fleshy; inflorescence racemose; "C" (2-)5; A (5) 8-10, connate basally, nectaries in depressions at base of G; G [2-5], opposite "C", placentation becoming free-central, 1 basal epitropous amphitropous ovule/carpel, placental obturator +, stigmas recurved; fruit a capsule; seeds arillate, exotesta ± palisade, unlignified, endotegmen enlarged, persistent; n = ?

1[list]/3. Central America, the Antilles (map: from Bedell 1980). [Photo - Fruit]

• Stegnospermataceae are more or less scandent or sprawling plants with rather fleshy leaves and racemose inflorescences that have apparently petaloid flowers with a more or less rotate corolla.

Chemistry, Morphology, etc. There is no nucellar cap. Are the seeds endospermic? For more information, see Friedrich (1956: cf. carpel position), Hoffmann (1977: general), Bedell (1980: general), Horak (1981: secondary thickening), Narayana and Narayana (1986: embryology) and Rohwer (1993a: general).

Stegnospermaceae look rather like Phytolaccaceae and the two have a somewhat similar gynoecium, but they are most obviously distinguishable by their flowers with "petals". They also have pollen with a prominent foot layer and massive endexine - this is thin in Phytolaccaceae. The ovule is epitropous, in pluricarpellate Phytolaccaceae it is apotropous (Rogers 1985). Like Caryophyllaceae, there are idioblasts in the wood with sphaerites; there is only diffuse axial xylem parenchyma.

Previous Relationships. Stegnospermaceae have often been included in Phytolaccaceae.

Wide-band tracheids are scattered through this group, occuring especially in the very succulent members. Limeaceae, Cactaceae and "Portulacaceae" have cells in rows along the dorsal junction of the seed.

LIMEACEAE Reveal   Back to Caryophyllales

Herbs or subshrubs; anthocyanins +; cork?; (secondary thickening normal); leaves spiral, stipules 0; "C" + (0), adnate to base of staminal tube; A connate basally; G [2-7], opposite sepals, (pseudomonomerous and secondarily divided [Limeum]), placentation axile, 1-3 ovules/carpel, antipodal cells persist, placental obturator +; fruit a membranaceous capsule or schizocarp; seeds arillate or not; testa with cells in rows along the dorsal junction; n = 9.

2/23: Limeum (21). Southern Africa, to Ethiopia, S. Asia, also Australia (Macarthuria) (map: from Culham 2007; FloraBase 2007).

For further information, see Hoffmann (1973: flower, growth), Behnke et al. (1983b: Macarthuria), Endress and Bittrich (1993: general, as Molluginaceae), and Hassan et al. (2005a: seed coat).

[Lophiocarpaceae [Barbeuiaceae [Aizoaceae [Gisekiaceae [Sarcobataceae + Phytolaccaceae + Nyctaginaceae]]]]] [Molluginaceae, Cactaceae, etc.]]: sieve tube plastids with globular crystalloids.

[Lophiocarpaceae [Barbeuiaceae [Aizoaceae [Gisekiaceae [Sarcobataceae + Phytolaccaceae + Nyctaginaceae]]]]]: ?

LOPHIOCARPACEAE Doweld & Reveal   Back to Caryophyllales

Anthocyanins?; inflorescence a raceme or leaf-opposed cyme [Corbichonia, inflorescence evicted]; C 0 [Lophiocarpus] or many; A many, centrifugal [Corbichonia], pollen tricolpate; G [2], 1-locular, ovule single, or [5], many ovules/carpel, placentation axile, placental obturator +; fruit an achene or capsule; seed arillate [Corbichonia]; exotestal cells radially elongated; n = ?

2/6. Africa, esp. S.W. Africa.

Chemistry, Morphology, etc. For Corbichonia flowers, see Ronse de Craene (2007), for embryology, see Narayana (1962) and Narayana and Lodha (1963: as Orygia - the ovules are almost anatropous and thinly crassinucellate).

[Barbeuiaceae [Aizoaceae [Gisekiaceae [Sarcobataceae + Phytolaccaceae + Nyctaginaceae]]]]: ?

BARBEUIACEAE Nakai  Back to Caryophyllales

Lianes; betalains?; libriform fibers, diffuse axial parenchyma, true tracheids +; sieve tube plastids with polygonal crystalloids[!]; cortical fibers +; druses +; leaves spiral; P 5; A many, pollen tricolporoidate; G [2], one ovule/carpel; fruit a loculicidal capsule; seeds 1 or 2, arillate, testa cells elongated, with sinuous anticlinal walls; n = ?.

1[list]/1: Barbeuia madagascariensis. Madagascar (map: from Culham 2007).

Chemistry, Morphology, etc. The plant dries black. See Hoffmann (1977), Rohwer (1993a: general, under Phytolaccaceae) and Carlquist and Schneider (2000: anatomy).

Aizoaceae [Gisekiaceae [Sarcobataceae + Phytolaccaceae + Nyctaginaceae]]: soluble oxalate accumulation; raphides +.

For soluble oxalate accumulation, see Zindler-Frank (1976).

AIZOACEAE Martynov, nom. cons.   Back to Caryophyllales

Leaf succulents; growth sympodial; CAM +; cork from inner cortex or endodermis; wood storied, rayless; fibers ± in bands; wide-band tracheid pith cells; cuticular waxes as ribbons or rodlets; stomata also para- and anisocytic; leaf trace bundles forming reticulum in cortex; leaves opposite, with bladder-like cells on epidermis, bases broad, membranous; growth sympodual; hypanthium +; P colored internally, often with subapical abaxial appendage ["horn"]; A often many, centrifugal, primordia 5, pollen tricolp(oroid)ate, nectary as ring; G septate, placental obturator +; seeds brown, exotesta ± palisade, or tangentially elongated; x = 8.

123[list]/ca 2020 - four subfamilies below. Esp. southern Africa, also Australia, etc., tropical and subtropical, arid. [Photos - Collection]

1. Sesuvioideae Lindley

Nodes also 3:3; stipules +; prophylls often prominent; (hypanthium +); A 5, alt. P, or primordia opposite P, or development rather chaotic; G (1-)[2(-5]), 2-many ovules/carpel; capsule circumscissile (compound, fused with spiny bracts - Tribulocarpus); seeds shiny black, arillate (not).

4/36: Trianthema (17), Sesuvium (12). Tropics and Subtropics; Sesuvium portulacastrum is pantropical on beaches (map: see George 1984; Hartmann 2001a, b; Fl. N. Am. 4: 2003). [Photos - Habit; Flower]

Synonymy: Sesuviaceae Horaninow

Aizooideae [Mesembryanthemoideae + Ruschioideae]: inflorescence not distinct from vegetative plant, bract/eoles foliaceous; A primordia alternating with T; fruit a hygrochastic capsule [see below].

2. Aizooideae

Bladder hairs with large terminal cell and multicellular stalk[?]; accessory lateral branches + [?]; inflorescence leafy; (A 10), G [2-10], to inferior, opposite P, 1 apical apotropous/basal-many ovules/carpel; (fruit septicidal - Gunniopsis; indehiscent - Tetragonia); seeds upright [?], (cell walls of seed coat little thickened).

7/135: Tetragonia (85). Drier parts of S. Africa, also Australia (Gunniopsis), few N. Africa and Asia Minor, N. America, etc. (Aizoon) (map: see George 1984; Hartmann 2001a, b). [Photo - Flower]

Synonymy: Galeniaceae Rafinesque, Tetragoniaceae Link

Mesembryanthemoideae + Ruschioideae: leaves very succulent; P green, sepalline, "C" [staminodial] many; G more or less inferior, nectary interrupted; x = 9.

3. Mesembryanthemoideae Ihlenfeldt, Schwantes & Straka

Distinctive alkaloids [in Phyllobolus, etc.] +; cortical bundles +; (succulent persistent green cortex in stem); flowers 4-5-merous, nectary hollow and ± shell-shaped [koilomorphic] (flat); G [(3-)4-5(-6)], semi-inferior, placentation axile; expanding keels of fruit purely septal.

1-11/100. S. Africa, a few species also W. South America, Australia, N. Africa, the Mediterranean and the Near East, naturalised in W. North America (map: see George 1984; Pascale Chesselet, pers. comm. 2004).

Synonymy: Mesembryanthaceae Burnett, nom. cons.

4. Ruschioideae Schwantes

Wide-band tracheids + [not in basal pectinations]; (leaves spiral); bladder cells uncommon; bracts/inflorescence often distinct; hypanthium 0[?], filaments papillate or hairy at base, nectaries often crest-like [lophomorphic], radial or annular; G [(3-)5-15(-25)], inferior, placentae basal or parietal; expanding keels of fruit largely valvar.

Ca 110/ca 1585: Ruschia (290-350), Conophytum (87-290), Lampranthus (180-220), Delosperma (155-165), Phyllobolus (150), Drosanthemum (100-110), Psilocaulon (65), Antimima (6-60). Southern Africa, esp. the western coastal Succulent Karroo (map: Pascale Chesselet, pers. comm. 2004). [Photos - Flower; Flower.]

• Aizoaceae are more or less prostrate herbs that may be recognised by their fleshy, opposite leaves the bases of which are membranous and usually surround the stem and the bladder-like epidermal cells. The flowers either have five perianth members that are green outside and colored inside or numerous linear "petals". There are usually many stamens, a more or less inferior and septate ovary, and a fruit that opens on moistening as the septal or other tissue swells.

Evolution. Aizoaceae, in particular Mesembryanthemoideae and Ruschioideae, dominate much of the Succulent Karoo of southwestern Africa, making up more than 50% of the species and up to an astounding 90% of the biomass. Interestingly, Klak et al. (2004) suggest that the radiation in Ruschioideae in S.W. Africa, at least, is both recent (3.8-8.7 million years before present) and very fast, indeed, the "meganiche" dominated by the whole family there - arid winter rainfall area with moderate temperatures - is only some 5 million years old (Ihlenfeldt 1994). Edaphic specialization - soils can vary considerably locally - may be involved in the diversification of Aizoaceae (Ellis & Weis 2006).

C₄ photosynthesis occurs in some members of this clade, perhaps especially Sesuvioideae (Sage et al. 1999).

Variation in growth characters - leaf size and shape, internode elongation, etc. - is considerable (Ihlenfeldt 1994). Although a distinction is sometimes made between plants with foliaceous bracts or bracteoles in which the inflorescence is not distinct from the rest of the plant, and plants with smaller bracts and distinct inflorescences (e.g. Hartmann 1993), it is unclear to me what the real growth characters are and where they go on the tree. The growth units of many species consist of paired leaves that are more or less flush with the surface of the ground; they can be almost invisible in the stony habitats in which they grow, being greyish or brownish and looking like pebbles themselves except when they flower - hence "flowering stones". The exposed surfaces of the leaves sometimes have distinctive "windows". In some species of Conophytum the leaves are almost completely connate except for a slit across the top out of which the flower, etc., appear. The bladder-like cells on the leaf surface ("idioblasts") may be involved with water uptake from dew or mist; other taxa may have massively-thickened outer walls that contain layers of calcium oxalate crystals (e.g. Ihlenfeldt & Hartmann 1982). In addition, individual cells may be variously papillate or the surface otherwise sculpted and/or with epicuticular waxes, the stomatal openings may be deeply sunken, etc. (e.g. Ihlenfeldt & Hartmann 1982; Hartmann 2002; Opel 2005a). Morphologically, these leaves are prophylls or bracteoles, the flower is terminal, and renewal shoots develop in the axils of the bracteoles so giving rise to the next flowering unit (Hartmann 2004, 2006 for a summary).

Ihlenfeldt (1983) and Hartmann (1988) have described the intricate morphology of the capsules of the [Aizooideae + Mesembryanthemoideae + Ruschioideae] clade, which are often hydrochastic. There are septal keels that reach from the central axis to the valve tips that expand when they absorb water. Seed dispersal is by "jet action" using the kinetic energy of falling raindrops (ombro[hydro]chory: Parolin 2006), but depending on the details of the capsule morphology, seeds may be dispersed different distances, and the ease of dispersal is inversely correlated with the distance the seed travels; in a few taxa this mechanism is replaced, and the fruits are dispersed as mericarps. There is also considerable variation in the establishment "strategies" of such seeds. Many Sesuvioideae have arillate seeds and are myrmechorous (Lengyel et al. 2009).

Chemistry, Morphology, etc. Studies of the wood anatomy of Aizooideae and Sesuvioideae are needed to clarify wood evolution in the family (see Carlquist 2007a), but see Rajput and Patil (2008) for a study of vascular development in Sesuvium portulacastrum. Wide-band tracheid pith cells in succulents (Aizoaceae, Cactaceae, Portulacaceae) are also found in the leaf away from the midrib in Aizoaceae; bands are narrow but very tall (= "wide"), so the cell lumen is locally very narrow (Mauseth et al. 1995 - similar in Hectorella [Montiaceae] - Carlquist 1998b). Studies of the perianth in Sesuvioideae show that the petaloid basal part is equivalent to a sheathing leaf base, and the apical "horn" to the rest of the leaf, rather as in monocot leaf development (cf. Vorlaüferspitze!); the petaloid B floral genes were not expressed, although they were in the petaloid staminodes of Ruschioideae (Frohlich et al. 2007). The androecium may arise as a ring meristem or as five separate primordia. Smets (1986) records the presence of a receptacular nectary disc, while Niesler and Hartmann (2007) suggested that the correlation of necatry morphology with major clades (see above) was not as strong as was thought; they found more or less flat nectaries in Glottiphyllum (Ruschioideae). Hartmann (1993) noted that a nucellar cap occurs in the family, but under this term he described the radially elongated cells of the nucellar epidernmis that are found in several other core Caryophyllales. Aptenia has a wet stigma.

For more information, see Schwantes (1957: esp. fruit dehiscence), Hegnauer (1964, 1989: chemistry), Hofmann (1973: morphology), Haas (1976: esp. flower and fruit), Bittrich (1986: general, esp. Mesembryanthemoideae), Hartmann (1993), Landrum (2001: wide band tracheids), Chesselet et al. (1995, 2002: esp. information on Mesembryanthemoideae and Ruschioideae) and Interactive Mesembs. The books edited by Hartmann (2001a, b) include thousands of photographs.

Phylogeny. I follow Klak et al. (2003) for basic groupings in the family; Aizoaceae s. str. (e.g. Chesselet et al. 1995) would seem to be paraphyletic. Tribulocarpus, which used to be in Tetragonioideae (for which, see Aizooideae above), is sister to the other Sesuvioideae, in which it is included here (Klak et al. 2003); it has an indehiscent fruit and so hardly surprisingly lacks arillate seeds. For a phylogeny of Sesuvioideae, see Hassan et al. (2005b). Tetragonia is embedded in Aizooideae (Klak et al. 2003), however, it has rays, it lacks the bands of fibers of other Aizoaceae, and has vascicentric parenchyma adjacent to the fibers (Carlquist 2007).

Apatesieae and Dorotheantheae are successively sister to the remainder of Ruschioideae, and they are not very speciose. The much more speciose core Ruschioideae - Drosanthemeae and Ruschieae - have a crest-like (lophomorphic) nectary, hygrochastic capsules with a distinctive anatomy (for which, see Kurzweil 2006) that release only a few seeds at a time, wide band tracheids are common (absent in sister taxa), and leaves that are cylindrical or trigonous and succulent, not more or less flattened (Klak et al. 2004; Chesselet et al. 2004) and without the bladder-like epidermal cells of the rest of the family. They also have lost the chloroplast rpoC1 intron (Thiede et al. 2007)- cf. Cactoideae! See Opel (2005a) for leaf anatomy and Opel (2005b) for a morphological phylogenetic analysis of Conophytum (Ruschioideae). Current estimates of species limits for this genus range from 87 to 290 (s)

Classification. There is a combined [list] of genera recognised in Mesembryanthemoideae and Ruschioideae, but genus (and species) boundaries are uncertain, both species and genus limits are difficult in the family. In the early twentieth century Mesembryanthemum included the whole of the Ruschioideae and Mesembryanthemoideae, and until recently the Mesembryanthemoideae, by far the smaller of the two subfamilies, was divided into numerous genera. However, Klak et al. (2007) in a comprehensive study of the subfamily, obtained quite detailed phylogenetic resolution within it. Mesembryanthemum itself, although quite a small genus, was polyphyletic, and any attempt to maintain current genera would, Klak thought, have caused the recognition of numerous and often poorly characterised taxa; only one genus was recognised. This decision may have to be revisited, since others think that clades there can be characterised (V. Bittrich, pers. comm.; Liede-Schumann & Hartmann 2009). Hammer in 1993 noted that there were then about 1,800 known populations of Conophytum (Ruschioideae) - for which there were 450 names; current estimates of species limits for this genus range from 87 to 290. For a general account of Lithops, see Cole and Cole (2005); for an infrageneric classification of Drosanthemum, see Hartmann (2007).

Gisekiaceae [Sarcobataceae + Phytolaccaceae + Nyctaginaceae]: 1 basal ovule/carpel; ORF 2280 sequence similarity, 210 bp deletion in chloroplast genome.

Family limits in this area may need adjustment; Douglas and Manos (2007) found only moderate support for the monophyly of Nyctaginaceae and vanishing little support for the monophyly of Phytolaccaceae (including Sarcobataceae). Similar relationships were found by Brockington et al. (2009), with Gisekia strongly supported as sister to the whole clade.

Note that Phytolaccaceae - Rivinioideae and Nyctaginaceae have gynoecia made up of a single carpel (Cuénoud et al. 2002), but if Sarcobataceae is placed somewhere around here, perhaps even within the already polymorphic Phytolaccaceae, its carpel number is a reversal...

GISEKIACEAE Nakai   Back to Caryophyllales

Prostrate herb; anthocyanins +; C₄ photosynthesis +; raphides +; leaves opposite; inflorescence leaf-opposed, dichasial; P 5; A 5(-15), alternating with P; G (3-)5(-10), pseudapocarpous; fruit muricate, achenial; exotestal cells tangentially elongated; n = 9.

1/5. Africa, Asia (map: from Culham 2007).

"Discordant" wherever it is put, but in some phylogenies to be placed with Phytolaccaceae-Rivinioideae (see Cuénoud et al. 2002)... See Gilbert (1993) for a review, Narayana (1962) and Hassan et al. (2005a) for ovule and testa morphology, and Narayana and Narayana (1988) for a little chemistry.

SARCOBATACEAE Behnke   Back to Caryophyllales

Thorny shrub; cork etc.?; wood rayless; ?stomata; plant monoecious, bracteoles 0; staminate flowers: inflorescence catkinate; flowers with peltate scales ["bracts"]; A 1-4, anthers long; pollen pantoporate, pore margins raised; carpellate flowers: flowers single; P tubular, bilobed [?bracteoles]; G [2], [?position]; funicle?; embryo green; n = 9.

1/2. S.W. North America (map: from Fl. N. Am. 4: 2003). [Photos - Collection]

Chemistry, Morphology, etc. Is Sarcobatus really worth placing in a separate family (cf. Behnke 1997)? Some information is taken from Carlquist (2000a).

Previous Relationships. Sarcobatus used to be included in Chenopodiaceae, but sieve tube plastids with globular inclusions, etc., suggest that it goes somewhere here.

Phytolaccaceae + Nyctaginaceae: cork subepidermal; stomata also paracytic; protein bodies in nuclei.

PHYTOLACCACEAE R. Brown, nom. cons.   Back to Caryophyllales

Herbs, vines (small trees); styloids and raphides +; cuticular waxes as platelets; leaves (opposite), conduplicate, (?stipules +); inflorescences (leaf-opposed), ± racemose; P 4-5(-10); A 2x P (= P, many, centrifugal); G (1)[-16], often pseudapocarpous, nucellar cap +, funicle?, (obturator +), styles ± gynobasic (style +); P and A persistent in fruit [?level]; embryo white; n = 9.

18[list]/65 - three groups below. Tropical and warm temperate, esp. America (map: see George 1984; Fl. N. Am. 4: 2003). [Photos - Collection]

1. Phytolaccoideae

Fibers vasicentric; P usu. 5, ovule apotropous; G [3-16]; fruit a berry.

4/31: Phytolacca (25). Chile, Mexico, or cosmopolitan (Phytolacca).

Synonymy: Sarcocaceae Adanson

2. Rivinioideae Nowicke

Habit various, inc. thorny trees; styloids, elongate crystals +; P usu. 4, (pollen pantoporate - Petiveria), G 1, stigma capitate [?always]; fruit various, inc. samaras, indehiscent.

9/13. Central and South America, Antilles, Florida, tropical Africa (some Hilleria), Australia, New Hebrides and New Caledonia (Monococcus).

Synonymy: Hilleriaceae Nakai, Petiveriaceae C. Agardh, Riviniaceae C. Agardh, Seguieriaceae Nakai

3. Agdestidoideae Nowicke

Liane; diffuse axial parencyma, true tracheids +; wood rayless; Ca oxalate?; cuticle waxes with ± rounded platelets; inflorescence branches cymose; P 4 (5); A 12-16(25); G [(3-)4], seminferior; fruit a 1-seeded achene with sepalline wings

1/1: Agdestis clematidea. S. U.S.A. to Nicaragua (map: from Fl. N. Am. 4: 2003; Culham 2007).

Synonymy: Agdestidaceae Nakai

• Phytolaccaceae can be recognised by their racemose inflorescences of apetalous flowers which have many, connate carpels - or a single carpel - each with a single basal ovule and a style; the fruit is often a berry. The plants are herbs, trees, or lianes, and the leaves tend to be rather thick and fleshy, lacking prominent fine venation.

Evolution. Fossil fruits from the Upper Cretaceous (late Campanian) of Mexico are similar to those of Phytolacca, Cevallos-Ferriz et al. (2008) noting a palisade exotesta and also a palisade layer in the tegmen.

Chemistry, Morphology, etc. Gallesia (Rivinioideae) smells of onions. Phytolacca is reported, probably incorrectly, to have glucosinolates (Fahey et al. 2001 for literature). In Petiveria (Rivinioideae) C. Agardh a nucellar beak is developed; both Monococcus and Petiveria have four perianth parts that are diagonally arranged. The pollen is similar in all subfamilies. The carpels of Phytolacca are initiated in a ring around the apex of the axis (Zheng et al. 2004)

See Hegnauer (1969, 1990: chemistry), Hoffmann (1977), Rohwer (1993a: general; he also includes Microtea - see Amaranthaceae), and Carlquist and Schneider (2000: anatomy).

Previous Relationships. Gyrostemonaceae, commonly with glucosinolates and now included in Brassicales very close to Resedaceae, have been linked with Phytolaccaceae by some authors in the past...

NYCTAGINACEAE Jussieu, nom. cons.   Back to Caryophyllales

Herbs to often rather weak-stemmed trees or lianes; (isoflavonoids +); (cork cortical); wood storied; (vessel elements with reticulate perforations); leaf wax crystalloids 0; flowers in cymose clusters; P connate, petaloid, lobes induplicate-valvate or contorted, (nectary on receptacle); G 1, ovule 1, basal, (unitegmic), antipodals ephemeral, embryo sac haustorium +, funicle short; fruit achene or nutlet, surrounded by persistent P; embryo green; n = (8-)11(-13+).

30[list]/395. Tropical to warm temperate (map: see Stemmerik 1964; George 1984; Fl. N. Am. 4: 2003; Culham 2007). [Photo - Fruit, Collection.]

1. Leucastereae Bentham & Hooker

Indumentum ± stellate; style thick/0, stigma crest-like; (P accrescent in fruit - Ramisia).

4/5. S.E. South America, esp. Brasil.

Boldoeae + The Rest: style long, slender.

2. Boldoeae Heimerl

Bracetoles 0; stigma inconspicuous (style 0, stigma fimbriate).

3/3. Mexico to Bolivia, the West Indies.

3. The Rest

(Gypsophily); leaves opposite (spiral - Bougainvilleae); (involucre +); P bipartite, tube stout, limb thin, 1-many, of varying lengths, pollen pantoporate (tricolpate, etc.), stigma capitate to crested; fruit closely surrounded by accrescent often mucilaginous basal part of P tube, rest withering; (endotesta thickened [Mirabilis]; testa multiplicative, unstructured [Pisonia]); (cotyledons unequal).

25/390: Neea (85), Guapira (70), Boerhavia (50), Mirabilis (45). Tropical to warm temperate, esp. herbs and shrubs in arid southwestern North America and arborescent genera in the Neotropics and Caribbean.

Synonymy: Allioniaceae Horaninow, Bougainvilleaceae J. Agardh, Mirabilidaceae W. Oliver, Pisoniaceae J. Agardh

• Nyctaginaceae may be readily recognised. The family includes herbs with swollen nodes, as well as lianes and trees. The leaves are often opposite and the wood is oxidising, i.e. it quickly turns orange/red-brown when cut. The leaves often dry dark grey and the venation is indistinct; the indumentum of the terminal bud is rich brown in color. The tubular, petaloid perianth with its induplicate-valvate or contorted aestivation is distinctive. The fruit proper, an achene, is covered by the usually accrescent basal part of the perianth. The result may a fruit that looks like a drupe, and this may be covered by glands that produce a very sticky secretion.

A xerophytic North American clade, especially common in S.W. North America, is noted for its abundance in dry or desert conditions; a number of species tolerate gypsum-rich soils. Taxa that flower in the evening or night (hence the common name, the "four o'clock family") are quite common (Douglas & Manos 2007). The subepidermal cells of the perianth may produce mucilage when the fruit is wetted, and this is especially notable in disseminules of the xerophytic North American clade. In species like Pisonia the pericarp in fruit is viscid and very sticky indeed; it is used as bird lime to catch birds.

Pisonieae may form ectomycorrhizae with various basiomycetes (Haug et al. 2005).

Chemistry, Morphology, etc. Carlquist (2004) examined secondary thickening in Nyctaginaceae in detail, and suggests that there is a lateral meristem that produces secondary cortex to the outside, and to the inside rays, conjunctive tissue, and a succession of vascular cambia, from which the more or less isolated areas of vascular tissue (but not rays) are derived. The single-flowered inflorescences of some species of Mirabilis can look remarkably like individual flowers: The green inflorescence bracts appear to be the calyx, and the brightly-coloured connate perianth then appears to be a sympetalous corolla. Some Nyctaginaceae (Boerhavinae, Nyctagineae) have pollen ca 200 µm long, about the largest in angiosperms outside the aquatic Cymodoceaceae (Alismatales). Abronia has only a single well-developed cotyledon, while the cotyledons of Pisonia and its relatives are unequal in size (and the embryo is straight).

See Hegnauer (1968, 1990) for chemistry, Vanvinckenroye et al. (1993) for floral development, and Bittrich and Kühn (1993) for general information.

Phylogeny. The basic phylogenetic structure of the family is becoming established. The South American Leucastereae and Mexican-Central American Boldoeae are successively sister taxa to the remainder of the family, positions that have moderate to strong support. Within the remainder of the family a North American xerophytic clade had very strong support, and in the whole group Bougainvilleae (paraphyletic), Pisonieae and Abronieae were embedded in a highly paraphyletic Nyctagineae (see also Levin 2000 for a more limited study).

Molluginaceae [Halophytaceae + Didiereaceae + Basellaceae + Montiaceae [Talinaceae [Portulacaceae [Anacampserotaceae + Cactaceae]]]] (= Cactaceae etc.): ?

MOLLUGINACEAE Bartling, nom. cons.   Back to Caryophyllales

Barely succulent herbs (shrubs); hopane saponins, C-glycosylflavonoids +; C₄ photosynthesis +; cork?; (secondary growth normal); pericyclic fibers +; (raphides +); hairs 0 or stellate; cuticle waxes as platelets or rodlets; prophylls prominent, ramifications made up of sympodial modules with definite numbers of leaves; leaves often pseudoverticillate, opposite or spiral, stipules membranaceous (0); P (4) 5, (-20 - Glinus); A (2-)5-10(-20), (alternate with P), filaments ± connate basally or not, nectary on adaxial surface, (pollen polyporate); G (1) [2-5(more)], opposite sepals or the median member adaxial, placentation axile, 1 [basal]-many ovules/carpel, antipodal cells ephemeral, funicles short, funicular obturator +, styles short; fruit a loculicidal capsule, or dehiscing by transverse slits, (nut); seeds arillate or not; exotestal cells undistinguished in shape; n = 9 (8 - Hypertelis).

9[list]/87: Mollugo (35), Pharnaceum (20). Largely S. Africa, Glischrothamnus NE Brasil, a few ± tropical to warm temperate (map: from ; Fl. N. Am. 4: 2003). [Photos - Habit & Flower]

• Molluginaceae are herbs or subshrubs with pseudoverticillate leaves that often have scarious stipules, flowers that may be quite showy but which generally lack any corolline whorl, and seeds that lack an obviously long funicle.

Evolution. C₄ photosynthesis has been reported from this clade (Sage et al. 1999).

Chemistry, Morphology, etc. Confirmation that anthocyanins are absent is needed. Para- dia- and anisocytic stomata sometimes occur. The stipule-like structures need examination. The androecium may be fasciculate.

Some information is taken from Adamson (1960: general), Hegnauer (1964, 1989, as Aizoaceae: chemistry), Bogle (1970: general), Richardson (1981: flavonoids), Behnke et al. (1983a: sieve tube plastids), M. Endress and Bittrich (1993: general), Narayana (1962) and Hassan et al. (2005a: seeds and ovules) and Vincken et al. (2007: saponins).

Phylogeny. Nepokroeff et al. (2002) found that Mollugo and relatives and Pharnaceum and relatives each formed a well-supported clade, but the two were only weakly linked; both are included in Molluginaceae above.

Taxonomy. The limits of the family have long been unclear. Most Molluginaceae as circumscribed in M. Endress and Bittrich (1993) are included here, but some genera (Limeum and relatives - Limeaceae; Corbichonia - Lophiocarpaceae) are elsewhere, albeit in this general part of core Caryophyllales. Polpoda, although also core Caryophyllales, is not incorporated in any description. Gisekia is probably to be placed with Phytolaccaceae-Rivinioideae (see Cuénoud et al. 2002).

Synonymy: Adenogrammaceae Nakai, Glinaceae Link, Pharnaceaceae Martynov, Polpodaceae Nakai

Halophytaceae + Didiereaceae + Basellaceae + Montiaceae [Talinaceae [Portulacaceae [Anacampserotaceae + Cactaceae]]]: leaves ± succulent; (CAM +); secondary growth normal; phloem parenchyma cells with phytoferritin; Ca oxalate crystals in stem epidermis; inner pair of bracteoles in the median plane [lacking subtending buds, and ± enclosing the flower] +; P petaloid.

Chemistry, Morphology, etc. Variation within this clade is complex (see also Nyffeler 2007, especially Ogburn 2007; Nyfeller et al. 2008; Ogburn & Edwards 2009). The stem cork cambium is superficial, although in some taxa it is outer cortical and in others epidermal (Ogburn & Edwards 2009). Most taxa have mucilage cells, but there may be interesting variation within the group as to exactly where such cells occur in the plant (Ogburn & Edwards 2009). "Portulacaceae" in the pectinations basal to Cactaceae have the pericarp strongly differentiated into two layers and they often have axillary hairs and bristles and even semi-inferior ovaries - and pantocolpate pollen. The axillary hairs of these "Portulacaceae" examined were mostly bi- or oligoseriate, while those of the few Cactaceae examined - but from three subfamilies - were uniseriate, although those of Pereskiopsis were biseriate at the base; the work of Chorinsky (1931) remains a useful early study on these structures, which are never vascularised.

Interpretation of the parts surrounding the flowers is complicated by the terms that have been used to describe them in the past. Paired structures closely associated with the flowers are described as braceteoles below; they are borne immediately below the flower and completely surround it. In the past, such bracteoles were often described as sepals. The whorl inside the bracteoles, usually 4- or 5-parted, is described as a perianth below, although its members are often fleshy and brightly coloured and have been called petals in the past. Pozner and Cocucci (2006) illustrate the bracteoles of Halophytaceae as being in the median plane, although they do not comment on this; this is the same position as the inner pair of bracteoles of Montiaceae, Portulacaceae, Didiereaceae, Basellaceae, etc. (e.g. Eichler 1878). Depending on the morphological interpretation of these structures and the topology of this part of the tree, the orientation of the bracteoles immediately subtending the flower could be a synapomorphy for the whole clade, including Halophytaceae (see above). The transverse bracteoles may have flowers in their axils, the median bracteoles always lack them. Interestingly, in at least some species of Anacampseros the median bracteoles are in the same plane as the bud-subtending bracteoles (Vanvinckenroye & Smets 1999).

Portulaca has an androecial ring primordium, and this is found in some Cactaceae and in species of Anacampseros, sometimes also with centrifugal initiation of stamens, other species have fewer stamens, which may be initiated in pairs (facing each other!) opposite the perianth members, or as single stamens alternating with them (Vanvinckenroye & Smets 1999). When there is the same number of stamens as perianth members, their positions relative to the carpels varies.

For general information about the old Portulacaceae, see Carolin (1987 [also a phylogenetic analysis], 1993), for chemistry, see Hegnauer (1969, 1990), and for anatomy, esp. focusing on the Talinaceae-Cactaceae clade, see Ogburn (2007).

Phylogeny. Relationships between members of this clade are complex, but cannot be understood through the lens of previous classifications. Of previous classifications, Basellaceae and Didiereaceae remain distinct, although a few African genera of Portulacaceae have recently been associated with the latter family; morphology is largely consistent with their new positions (see Didiereaceae for details). Portulacaceae are strongly paraphyletic, and erstwhile members occupy several pectinations on the clade immediately basal to Cactaceae, while within Cactaceae Pereskia is paraphyletic.

Hershkovitz and Zimmer (1997) studied relationships in much of this group; if Cactaceae were recognised, "Portulacaceae" would be paraphyletic (see also Appelquist & Wallace 1999, 2001). Nevertheless our understanding of the details of the phylogeny of the group remained poor. Hershkovitz and Zimmer (2000: ribosomal DNA, Cactaceae not included) found little major phylogenetic structure in a study of American "Portulacaceae", yet it was clear that there must have been a number of major dipsersal/colonization events in that group; Hershkovitz (2006) found the same general pattern as he focused on W. American "Portulacaceae" from the Andean region - there were perhaps half a dozen clades in that region, but no major groupings beyond that. Cactaceae, Didiereaceae and Portulacaceae remained a closely entwined complex (Appelquist & Wallace 2000). Indeed, they can all be intergrafted (Anderson 1997), although natural grafts of such unlikely subjects as Boscia (Brassicaceae) with Colophospermum (Fabaceae - Caesalpinioideae) and Combretum (Combretaceae) are also reported (Wissels & Potgeiter 1997)! See also Cuénoud et al. (2002) for relationships in this area, e.g. of Halophytum. Portulaca and Pereskia (but not Claytonia) share a 500 bp chloroplast DNA deletion in the rbcL gene (Wallace & Gibson 2002 for details and references), a potentially informative molecular marker.

Recent work is beginning to clarify relationships within the group. Cactaceae + Talinum + Portulaca + Anacampseros, etc., form one major clade that is rather well supported (Hershkovitz & Zimmer 1997; Appelquist & Wallace 2001). Nyffeler (2007: three genes, two compartments) found some support for a topology [Talinum and relatives [Portulaca [Anacampseros and relatives + Cactaceae]]], although the topology was different when the mitochondrial nad1 data were analyzed alone. Support for the [Anacampseros and relatives + Cactaceae] clade was appreciable in the combined analysis (78% bootstrap), where the chloroplast signal predominated. The taxa recognised below are consistent with the topology suggested by Nyffeler (2007). In a study involving a considerable amount of data but rather skimpy sampling, [Portulacaceae + Talinaceae] had 98% boostrap support, with Claytonia sister to the whole clade, even including Halophytaceae (Brockington et al. 2009), while Nyffeler and Egli (2009) found little resolved in the way of relationships except in the Talinaceae-Cactaceae area, and support for the monophyly of Didieraceae and Montiaceae was not strong. The relationships Butterworth and Edwards (2008) found in the Cactaceae area are [Anacampserotaceae [Talinacaeae [(weak support)Portulacaceae + Cactaceae]]]; there was no outgroup, so Anacampserotaceae appeared to be paraphyletic. More studies are clearly needed, and details of the phylogeny here are obviously rather notional.

HALOPHYTACEAE A. Soriano   Back to Caryophyllales

Herb; wood rays 0; stomata?; plant monoecious; staminate flowers: inflorescence densely spicate; transverse bracteoles absent; P 4, barely petaloid, valvate-decussate, stamens alternate with perianth members, anthers extrorse, porose, dehiscence by contraction of the connective, endothecium with frame-shaped thickening on anticlinal walls, pollen cuboid, hexaporate, pistillode 0; carpellate flowers: inflorescence fasciculate, pedicels 0; P 0; G [3], unilocular, 1 basal ovule, style +, stigmas spreading; fruit a nutlet, several becoming enclosed by inflorescence axis; n = 12.

1[list]/1: Halophytum ameghinoi. Argentina (map: from Zuloaga & Morrone 1999).

Chemistry, Morphology, etc. The wood is rayless, and relationships with Aizoaceae - also with rayless wood - have been suggested (Gibson 1978). There are no endothecial thickenings at all on cells adjacent to the openings of the anthers (Pozner & Cocucci 2006).

Some information is taken from Bittrich (1993: general); Pozner and Cocucci (2006) describe the staminate flower in considerable detail, including the distinctive endothecial thickenings and anther dehiscence.

Didiereaceae + Basellaceae + Montiaceae [Talinaceae [Portulacaceae [Anacampserotaceae + Cactaceae]]]: (plants with tuberous roots [at least some species in all families]); mucilage cells +; leaves amphistomatic [?Basellaceae}; median P abaxial [opposite outer median bracteole]; pollen pantocolpate, no funicular obturator; 6-bp deletion in ndhf gene.

Evolution. Taxa with fleshy roots are scattered throughout the whole clade, being found in all families, as well as in all subfamilies of Cactaceae (e.g. Nyffeler et al. 2008).

For CAM in Portulacaceae s. l., i.e., effectively most of this clade, see Guralnick and Jackson (2001). CAM cycling is common; this occurs when plants do not completely shut their stomata during the day, and carbon is fixed at night not from atmospheric but from respiratory CO₂.

Chemistry, Morphology, etc. For information on the vegetative plant, see Nyffeler et al. (2008). Nowicke (1996) described a number of pollen characters that are shared in the group (her Portulacinae), although they may also occur outside it: Columellae either narrowed towards the middle or expanded towards the base, sometimes fused; pollen with granular internal surfaces; perforated foot layer; non-apertural endexine very thin ("thread-like").

Previous Relationships. Classifications in the past generally recognised Cactaceae (with "Pereskia" s.l. as sister to the rest of the family), a broad Portulacaceae, Didiereaceae s. str. (i.e., Malagasy taxa only), Basellaceae, and the Antipodean Hectorellaceae.

Didiereaceae + Basellaceae: stomata paracytic; ovary with single basal ovule; fruit single seeded, indehiscent.

DIDIEREACEAE Radlkofer, nom. cons.   Back to Caryophyllales

Woody, ± stem succulents, often thorny, (deciduous; short shoots +); facultative CAM; "tannin", methylated flavonoids +; (wide band tracheids +); cork cambium initiation precocious; tanniniferous cells +; leaf stomata parallelocytic, transversely oriented; cuticular waxes as ribbons or rodlets; short shoots common, (persistent paired prophylls); plant (gyno)dioecious, (inflorescence fasciculate); (transverse bracteoles absent); P 4-5, petaloid, annular nectary at base; A 5 [alternating with P]-12 in a single whorl (many - Calyptrotheca), from ring primordium, basally connate and with adaxial nectaries, (pollen 5-7-zonocolpate, polyporate); G [(2-4)], (1[-2] ovules/carpel), stigmas ± peltate, fringed; fruit achenial, (circumscissile capsule, K strongly accrescent - Calyptrotheca); seeds with funicular strophiole or aril; perisperm ± absent; n = 22, 24, often wildly polyploid.

7/16. Madagascar, South Africa, E. Africa. [Photos - Collection.]

• Didiereaceae are usually more or less stout-stemmed plants with often "spiny" short shoots; the flowers are usually imperfect and the one-seeded fruits are usually indehiscent.

Chemistry, Morphology, etc. There are questions as to the morphology of the "thorns" of Didiereaceae s. str. Rauh (1983) calls them spines, being either leaves on short shoots and paired and stipular. However, Alluaudia has leaves subtending an axillary thorn, and later paired, lateral, and apparently prophyllar leaves develop from an axillary bud below the thorn. The outermost pair of perianth segments (the bracteoles immediately associated with each flower) is in the median plane, and large bracteoles of the inflorescence ("large bracts") may be obvious, as in Portulacaria. In Didiereaceae s. str. there are four stamens clearly alternating with the perianth members.

See Rauh and Schölz (1965: growth, morphology, etc), Hegnauer (1966, 1968, 1989: chemistry), Kubitzki (1993b: general), Schatz (2001: generic descriptions), Erbar and Leins (2006: floral ontogeny), and Nyffeler and Eggli (2009: general).

Phylogeny. This clade includes a morphologically distinctive monophyletic group of plants that are Didiereaceae in the old sense. Immediately basal to them are some African ex-Portulacaceae - [[Ceraria (Africa; looks like Didiereaceae s. str.!) + Portulacaria (both with tricolpate pollen)] [Calyptrotheca (polyporate) + Didiereaceae (in the old sense)]]. Didiereaceae should be expanded to include the whole clade (Appelquist & Wallace 2000, 2003). Appelquist and Wallace (2003) provide a subfamilial classification for the expanded Didiereaceae.

Synonmy: Portulacariaceae Doweld

BASELLACEAE Rafinesque, nom. cons.   Back to Caryophyllales

Vines with swollen rhizomes or tubers; successive cambia +; cork cambium initiation timing?, in outer cortex; vascular bundles separate, bicollateral; leaf stomata paracytic, ?oriented; cuticle wax crystalloids 0; (leaves also opposite, conduplicate [Anredera]; margin serrate, with glands - Tournonia); inflorescence racemose, (cymose - Tournonia); flowers small; P (4-)5(-13), connate; A 4-9, often equal and opposite perianth members, adnate to it; pollen hexacolpate/porate (cuboid); (style single, branches short), stigma ± capitate or lobed; fruit an utricle, surrounded by persistent (bracteoles and) K, (K fleshy); exotesta thickened, endotesta ± thickened; perisperm scanty, starch grains clustered, embryo green; n = 12, 22.

4[list]/19. Africa, New World, apparently introduced into India-East Asia (map: from Sperling 1987; Fl. N. Am. 4: 2003). [Photos - Collection]

• Basellaceae are more or less succulent and viney plants with small flowers and a single seeded fruit surrounded by the persistent perianth.

Chemistry, Morphology, etc. Sperling (1987) reports both bracteoles and large, paired structures immediately surrounding the perianth (see also Eriksson 2007). The interpretation of floral morphology differs - cf. Friedrich (1956), LaCroix and Sattler (1988), and Sperling and Bittrich (1993).

For general information, see Bogle (1969), Sperling (1987), Eriksson (2007), and Nyffeler and Eggli (2009). For chemistry, see Hegnauer (1964, 1989), for wood anatomy, see Carlquist (1999), for successive cambia, see Jansen et al. (2000c).

Taxonomy. Eriksson (2007) includes a synopsis of species in the family.

Synonymy: Anrederaceae J. Agardh, Ullucaceae Nakai

Montiaceae [Talinaceae [Portulacaceae [Anacampserotaceae + Cactaceae]]]: ?

MONTIACEAE Rafinesque   Back to Caryophyllales

Annual to perennial herbs, often with swollen roots and basal rosette leaves, internodes short (subshrubs, leaves not succulent - Montiopsis); photosynthesis?; cork cambium initiation delayed; secondary growth little; vessel elements?; nodes 1:1 [Lyallia]; plant glabrous; stomata paracytic, longitudinally oriented; cuticle waxes as procumbent platelets; leaves often with clasping bases; inflorescences terminal, (monochasial) cymose, or single (axillary) flower; (transverse bracteoles absent); P 4-5(-9), petaloid, (basally connate), A equal and opposite perianth members, (or 1 fewer, alternating with P - Hectorella, Lyallia; -100), basally connate or not, pollen also 3-colpate, pantoporate, G [2-8], (placentation free central, with 4-7 ovules), funicle?, style ± developed, styles diverging; fruit a [kind?] capsule, or circumscissile, or 1-seeded, indehiscent; outer wall of exotesta thickened and with stalactite-like projections; n = 6-13, etc.

ca 10/: Claytonia (27). Especially Western North and South America, also the Antilles and the Subantarctic Islands (map: from Hultén & Fries 1986; Fl. N. Am. 4: 2003; Miller & Chambers 2006, incomplete). [Photo - Collection, but not all.]

Chemistry, Morphology, etc. Hectorella has both spiral phyllotaxis and a closed vascular system, a very unusual combination (Beck et al. 1982). The inflorescence of both Hectorella and Lyallia may be a reduced cyme; there are alternate/distichous bracts below the flower, and the latter genus may have more than one flower per axil (Skipworth 1961; Wagstaff & Hennion 2007). The paired bracteoles below the flower in these two genera are clearly described and illustrated as being transverse (lateral) by Skipworth (1961), but the new family Hectorellaceae their position was described as being ad/abaxial (median) by Philipson and Skipworth (1961). Montiopsis can have trilobed bracteoles. Schnizlein (1843-1870: fam. 206) draws carpels alternating with the perianth members or the median member abaxial (Claytonia). Claytonia virginiana shows extreme variation in chromosome numbers - 2n = 12-ca 191 (Bogle 1969).

Some information is taken from Philipson (1993) and Lourteig (1994); for pollen, see Nilsson (1967), and for phylogenetic relationships of the western American taxa, see Hershkovitz and Zimmer (2000); see Nyffeler and Eggli (2009) for general information.

Phylogeny. West American members of the old Portulacaceae placed here include Montia, Lewisia, Phemeranthus, etc. (e.g. Hershkovitz 1993, 2006). Recent work (Applequist et al. 2006, see also Nepokroeff et al. 2002) assigns the New Zealand-Antarctic Hectorellaceae, previously of uncertain relationships, to this clade (as a new tribe of Portulacaceae). The clade has strong support, as does the sister group relationships between Phemeranthus and the nine other genera included in the ndhf analysis. Although flower position (axillary) and bracteole and stamen position of Hectorellaceae differ from that of Montiaceae, and the gynoecium is unilocular, the anatomy of the two is very similar (Carlquist 1998b). O'Quinn and Hufford (2005) outline the phylogeny of Claytonia (tricolpate) and its sister taxon, Montia (pantocolpate).

Synonymy: Hectorellaceae Philipson & Skipworth

Talinaceae [Portulacaceae [Anacampserotaceae + Cactaceae]]: (roots tuberous); plant mucilaginous; stomata parallelocytic; P petaloid; fruit covered by dried P, pericarp 2-layered, exocarp ± caducous.

TALINACEAE Doweld   Back to Caryophyllales

Herbs to (lianescent) shrubs, underground parts often tuberous; cork cambium initiation timing variable, (cortical); tanniniferous cells +; C₃/CAM cycling; leaf stomata unoriented; leaves with paired axillary scales; (ovary septate - Talinella); fruit (mucilaginous, indehiscent - Talinella), epidermis papillate; seed strophiolate; n = 8.

1/27. America and Africa. [Photo - Collection, but not all.]

Chemistry, Morphology, etc. The paired, axillary scales are in fact the very tips of the prophylls. See Vanvinckenroye and Smets (1996) for floral development, and Nyffeler and Eggli (2009) for general information.

Phylogeny. Talinella is nested within Talinum (Nyffeler 2007).

Portulacaceae [Anacampserotaceae + Cactaceae]: loss of pericyclic fibers; (sclereids in stem cortex); leaves with axillary bi- or multiseriate hairs/scales +.

Chemistry, Morphology, etc. Non-lignified parenchyma cells, often in bands, occur in the wood of at least some Portulaca and in Cactaceae (Melo-de-Pinna 2009). There is variation in the chloroplast infA gene in this clade, with both insertions and duplications (Ocampo 2009). For hairs associated with the leaves, whether axillary or lateral, see also Rutishauser (1981).

PORTULACACEAE Jussieu, nom. cons.   Back to Caryophyllales

Succulent (annual) herbs, (roots tuberous); cork cambium initiation delayed; C₄/CAM cycling; (axillary hairs 0); leaf stomata transversely oriented; (internodes short); leaves ± terete; inflorescence ± capitate, with involucre, (transverse bracteoles absent); (P 4-8); capsule circumscissile, pericarp undifferentiated; aeed with hilar aril; anticlinal walls of testa sinuous; n = (8-)10.

1/40-100. Worldwide, but especially tropical and subtropical North and South America. [Photo - Collection, but not all.]

• Portulacaceae are succulent herbs with capitate inflorescences, flowers with two "sepals" and usually five "petals", and circumscissile capsules.

Chemistry, Morphology, etc. See Nyffeler and Eggli (2009) for general information.

Evolution. There have been several switches to C₄ photosynthesis in this clade (Ocampo & Columbus 2009).

Phylogeny. For relationships within Portulaca, see Ocampo and Columbus (2009); taxa with opposite leaves and those with spiral leaves form separate clades.

Previous Relationships. For taxa included in earlier circumscriptions of Portulacaceae, see Nyffeler and Eggli (2009).

Anacampserotaceae + Cactaceae: A many.

ANACAMPSEROTACEAE Eggli & Nyffeler   Back to Caryophyllales

Subshrubs with ± tuberous roots, (stems fleshy); rosette plants, internodes short; (wide band tracheids +); cork cambium initiation precocious, (cortical); facultative CAM, ?C₄; (leaf-associated hairs 0, but leaf with concave adaxial scale); leaf stomata transversely oriented; leaves (opposite), ± terete, (with axillary scales - Avonia); (A 5-15), stigma receptive on both surfaces; seeds pale-coloured, exotesta ± separate from endotesta, thin walled, unlignified; embryo only slightly curved, not surrounding the poorly developed perisperm; n = 9.

3/32: Anacampseros (30). C. and S. Australia, Somalia to South Africa (most species), S. South America, N. Mexico and S.W. U.S.A. (map: from Gerbaulet 1992a, 1993; Fl. N. Am. 4: 2003).

• Anacampserotaceae are often rather small, fleshy plants with two "sepals" surrounding five "petals", rather complex fruits in which two layers of the pericarp separate periclinally, and pale-coloured seeds in which two layers of the seed coat also separate pericilinally.

Chemistry, Morphology, etc. For general information, see Gerbaulet (1992a) and Rowley (1994), for biogeography, see Gerbaulet (1992b), and for ecology, Gerbaulet (1993). For general information, references, etc., see Nyffeler and Eggli (2009).

Phylogeny. Generic limits in this clade are difficult, since all six species of Grahamia included in the analysis of Nyffeler (1997) formed a perfect basal pectination, and at least some nodes have good support... On the other hand, this helps in reconstructing the basal character states for the clade.

Classification. For genera, see Nyffeler and Eggli (2009).

CACTACEAE Jussieu, nom. cons.   Back to Caryophyllales

± Woody; C₃/CAM cycling; rays wide and tall; calcium oxalate as whewellite [CaC₂O₄.H₂O]; nodes often with two or many traces; epidermis (inc. cuticle) thick-walled, hypodermis +, druses + (0); cuticular waxes as ribbons or rodlets, also thick prostrate plates; short shoots [areoles] with spines [= leaves] and [?mostly] uniseriate hairs, (spines continuing to be produced at long-lived areole); long shoot leaves fleshy; median bracteoles 0; P several-numerous, spiral, sepaline outside and petaline inside [modified bracts], (disc +); G [5-many], inferior, placentation ± parietal, many ovules/carpel, stigma wet; fruit usu. baccate, surrounded by stem tissue [with areoles, etc.], pericarp not two-layered; funicles fleshy; endotegmic cell walls thickened or not; n = 11; 6 kb inversion in large single copy region of plastid genome.

111[list]/1500 - five groups below. Nearly all New World, esp. arid conditions, but also rain forest climbers and epiphytes, perhaps a few also Old World. [Photos - Collection]

1. Northern, Caribbean Pereskia, = Rhodocactus

Cork cambium initiation precocious, cortical; stem stomata when present parallely oriented, opuntioid [apart from the innermost pair of cells, subsidiary cells arranged in a more or less random manner], leaf stomata randomly oriented; pollen colpate.

1/7. Mexico and the Caribbean, Brasil. (map: from Leuenberger 1986, 2008; Edwards et al. 2005)[Photo - Leaf, Flower, Fruit]

Pereskioideae [Opuntioideae [Maihuenioideae + Cactoideae] - "caulocacti": cork cambium initiation delayed; cortical sclereids 0; stem mucilage cells +; stem cuticle often thick; stomata in stem epidermis common.

2. Pereskioideae Engelmann

(Tuberous roots); phloem sclereids +; stem stomata parallely oriented, opuntioid, leaf stomata randomly oriented; lamina supervolute; A centrifugal, from 5 primordia, pollen colpate, ovary ± superior.

1/9. Andean, S. South America, Andean, S. South American Pereskia, = Pereskia s. str. (map: from Leuenberger 1986, 2008; Edwards et al. 2005).

Opuntioideae [Maihuenioideae + Cactoideae]: stems succulent, internodes short; hypodermis collenchymatous; cortical chlorenchyma forming mesophyllar tissue with intercellular spaces; wide band tracheids in secondary xylem with annular thickenings [at least in seedlings]; leaves terete; inflorescences axillary, flowers single; hypanthium +; A from ring primordium [?Cactoideae].

3. Opuntioideae Burnett

Stems articulated, roots often tuberous; stem stomata parallely oriented, opuntioid, leaf stomata parallely oriented; leaves small, soon deciduous (subpersistent, large, with blade - Pereskiopsis); areoles with glochids [minute, retrorsely-barbed bristle-spines]; pollen polyporate; seeds ± covered by bony funicular "aril", outer periclinal wall of testa little thickened; (cotyledons are storage organ); deletion of the accD gene.

16/225: Opuntia (200). Canada, almost the Arctic Circle, to Patagonia. (map: see Thorne 1973; F. N. Am. vol. 4. 2003.) [Photo - Flower, Flower.]

Synonymy: Nopaleaceae Schmid & Curtman, Opuntiaceae Martynov

Maihuenioideae + Cactoideae:

4. Maihuenioideae P. Fearn

Caespitose shrubs; cork cambium formation not delayed; photosynthetic parenchyma at base of areolar crypts; general stem stomata 0, some in areolar crypts, leaf stomata transversely oriented; leaves persistent, with cylindrical reticulum of bundles, the external xylem surrounding central mucilage reservoir; pollen tricolpate; funicles in fruit long, mucilaginous.

1/2. Argentina and Chile (map: from Leuenberger 1997, 2008).

5. Cactoideae Eaton

Stem growth indeterminate [distribution?]; (roots tuberous); plant leafless [leaves up to 1.5(-2.5) mm long when mature]; stem stomata unoriented [transverse - epiphytic taxa], parallelocytic; leaf stomata?; pollen 3-polycolpate(-porate); funicles?; testa interstitially pitted or cratered, outer periclinal wall much thickened.

92/1250. New World, S. Canada to S. W. U.S.A. southwards; perhaps few in Africa, Madagascar, and Sri Lanka - only Rhipsalis.

5A. Blossfeldieae Butterworth

Vascular bundles lacking cap of phloem fibres; epidermis (inc. cuticle) thin-walled, soon replaced by cork cambium, hypodermis 0; photosynthetic parenchyma at base of areolar crypts; stem stomata few, at the base of areolar crypts, leaf stomata 0; seeds with a funicular aril [strophiolate], testa with one short narrow hair/cell; n = 33.

1/2. Bolivia to Argentina, eastern Andes (map: from Leuenberger 2008).

5B. Cacteae Reichenbach + The Rest.

Ribbed stems common; calcium oxalate often as weddellite [CaC₂O₄.2H₂O]; (alkaloids +); (wide band tracheids 0); cortical vascular bundles +; cortex broad, succulent, (inner cortical cells collapsible); (hypanthium 0), pollen 3-polycolpate(-porate); (seeds arillate), funicles?; testa interstitially pitted or cratered, outer periclinal wall much thickened; (hypocotyl storage organ); rpoC1 intron lost.

91/1250: Mammillaria (150), Echinopsis (50-100), Echinocereus (50), Gymnocalycium (50), Rhipsalis (50). New World (S. Canada to S. W. U.S.A. southwards), esp. Mexico, Brasil, Peru-Bolivia. Rhipsalis, epiphytic and bird-dispersed, with a few (?native) spp. in Africa, Madagascar, Sri Lanka (map: see Thorne 1973; Bathlott 1983 [Rhipsalis]; Fl. N. Am. vol. 4. 2003.). [Photo - Plant, Flower.]

Synonymy: Cereaceae de Candolle & Sprengel

• Cactaceae can be recognised by their usually stout and very fleshy stems, axillary areoles of spines and hairs, and flowers that usually have an inferior ovary and many stamens and "petals"; the fruits are fleshy.

Evolution. Diversification in Cactaceae is estimated to have occured in the mid-Tertiary ca 30mybp (Hershkovitz & Zimmer 1997, which see for other estimates), so [Maihuenioideae [Opuntioideae + Cactoideae]] may be a rather young group.

Although Cactaceae are pre-eminently a group of arid climates in the New World, a number of taxa grow in more or less humid forest as lianes and epiphytes. The family is also a notable component of seasonally dry tropical forests (Pennington et al. 2009). Edwards and Donoghue (2006; see also Edwards 2006 and Edwards & Diaz 2006) discuss the eco-physiological evolution of Cactaceae (for which, also see Nobel 1988 and references). They emphasize that the leafy Pereskia and Rhodocactus clades have high photosynthetic water use efficiency, very high minimum leaf water potentials, and conservative stomatal behaviour (stomata open only when there is available water, at night or after rain). Other features of potential functional interest include the production of large amounts of water conducting tissue relative to leaf area, and perhaps also CAM-type photosynthesis. This latter is poorly developed in Pereskia, etc., but is well developed in the stem of succulent cacti (Martin & Wallace 2000). Most taxa have a shallow rooting system that allows quick uptake of water after rain. In some Cactaceae-Cactoideae, at least, the primary root is determinate in growth, perhaps facilitating the rapid development of lateral roots (Rodríguez-Rodríguez et al. 2003). In many Cactaceae there are "rain roots", water-absorbing roots that develop quickly after rains, and dying when the soil dries up; in such roots the apical root also usually aborts (Shishkova et al. 2008). A skeletal root system of perennial, cork-covered roots persists (Gibson & Nobel 1986). Diversification of the "leafless" Cactaceae may be as much connected with the development of a cauline water storage system as with the evolution of the other ecophysiological features just mentioned (and of course one would like to know much more about the physiology and anatomy of the clades immediately basal to Cactaceae...).

Fleshy, water-storing roots are scattered in Cactaceae, including Pereskia s. str. The taxa involved are usually small plants, and although the tissue involved varies considerably, suggesting the independent origin of such structures, it is modified secondary vascular tissue (Stone-Palmquist & Mauseth 2002). In Opuntioideae these swollen roots - see, for example, the appropriately-named Maiheuniopsis clavarioides - seem to be particularly common in the taxa of the basal pectinations (Griffith & Porter 2009), and they are also common in taxa in the pectinations immediately basal to Cactaceae as a whole (see also Griffith 2004).

Calcium oxalate metabolism in Cactaceae and relatives is potentially interesting. There is variation in the degree of hydration of calcium oxalate, and the general distribution of the two crystal forms found, weddellite and whewellite, may be systematically interesting (Rivera and Smith 1979, they caution that only druses were examined; Monje & Baran 2002; esp. Hartl et al. 2007). Some Cactaceae accumulate positively massive amounts of calcium oxalate crystals - e.g. ca 85% of dry weight in Cactus senilis.

In Opuntioideae, the leaves of Pereskiopsis are large, petiolate and bifacial, those of Quiabentia (the two may be sister taxa - e.g. Butterworth & Evans 2008) are terete, unifacial but also persistent, in other Opuntioideae they are terete and deciduous. These more complex leaf types may in fact be derived (Griffith & Porter 2009), and at the same time those of Pereskia s.l., although similar to those of Pereskiopsis, may represent a more plesiomorphic condition (but cf. Griffith 2004, 2008). Complicating the issue is the restriction of stomata to leaves and adjacent to areoles in these leafy Opuntioideae (Griffith 2008). Although one commonly thinks of Cactoideae in particular as being leafless, Mauseth (2007) has shown that most do have leaves that are up to 1.5(-2.5) mm long when mature, although these are still mostly shorter than the terete leaves found in Opuntioideae. Despite their small size, some of these leaves of Cactoideae have a rudimentary lamina with vascular tissue, stomata, etc.

Animal dispersal of the fruits is universal in the family; in some Cactoideae in particular the seeds may germinate while still in the fruit, a form of vivipary (Cota-Sánchez et al. 2007). The distribution of Rhipsalis with its miseltoe-like fruits has occasioned much discussion. Although largely diploid in the New World (its center od diversity is eastern Brazil), it is polypoid in the Old World (Barthlott 1983)

Chemistry, Morphology, etc. The roots of at least some Cactoideae have an open type of apical meristem (Rodríguez-Rodríguez et al. 2003). Cactaceae have young stems with very broad apical meristems 400-1500 µm across, rather broader than those of other flowering plants (Gifford 1954; Clowes 1961: sampling poor). The cortex is particularly variable in Cactoideae. Cuticle waxes in the form of spiral rodlets occur in Cereeae.

Note that there is potentially interesting variation within the parallelocytic stomata "type" so common here. In both Pereskia and Opuntioideae the subsidiary cells do not, or only barely, overlap the ends of the guard cells, the "opuntioid" stomatal type (it could be called brachyparallelocytic!), whereas in other Cactaceae the subsidiary cells successively more broadly invest the poles of the whole stomatal apparatus. Wallace and Dickie (2002) note that the stomata of Opuntioideae are unique (see above). There is also variation in stomatal orientation. The stomata on the stems of Pereskia and Opuntioideae are oriented parallel to the long axis of the stem, while in Cactoideae they tend to be unoriented (Eggli 1984).

The inferior ovary of Cactaceae is a text-book example of receptacular epigyny in angiosperms (Boke 1964), where the tissue investing the ovary is of axial origin. This is clear in genera like Opuntia where areoles cover the inferior ovary; it is as if the ovary has sunk into the stem. The hypanthium so conspicuous in some Cactoideae, etc., is a development of this axial tissue; an obvious hypanthium is absent from Cactoideae like Rhipsalis. Placentae may alternate with septae, and/or be more or less basal; Leins and Schwitalla (1988) interpret the condition in which ovules are associated with incomplete septae proceeding from the ovary wall as the plesiomorphic condition for Cactaceae. However, the evolution of this inferior ovary needs to be re-examined given the paraphyly of Pereskia s.l., with some species of Pereskia s. str. having superior ovaries (see Edwards et al. 2005).

For general information, see Barthlott and Hunt (1993), Anderson (2001) and Nobel (2002), as well as Hunt et al. (2006) for an excellent summary of the family, including a volume of superb photographs of nearly all species taken mostly in the wild. For Pereskia s.l., see Neumann (1935: pollen, etc., development), Leuenberger (1986: general), and Mauseth and Landrum (1997: "Relictual" anatomical characters), and for Opuntioideae, see Hunt and Taylor (2002: general). For chemistry, see Hegnauer (1964, 1989), for pollen, see Leuenberger (1976: general) and Garralla and Cuadrado (2007: Opuntioideae), for seed morphology, see Barthlott and Voigt (1979), for that of Opuntioideae, see Stuppy (2002), and of Cactoideae, see Barthlott and Hunt (2000), for stomata in general, see Eggli (1984), for placentation, see Leins and Schwitalla (1988), for general anatomy, see Terrazas and Arias (2003 - esp. Cactoideae), for general antomy in Opuntioideae, see Mauseth (2005), for wood anatomy there, see Mauseth (2006c), for wide-band tracheids in particular, see Mauseth (2004) and Godofredo and Melo-de-Pinna (2008), and for structure-function relationships, see Mauseth (2006a). For Maiheunia some information is taken from Gibson (1977: anatomy), Mauseth (1999: anatomy), and Leuenberger (1997: general); Taylor (2005) is a good introduction.

Phylogeny. Phylogenetic relationships within Cactaceae are still rather unclear, with chloroplast and nuclear genes sometimes suggesting different major clades (see Butterworth 2006a for a summary). A study by Nyffeler (2002) found rather weak support for the subfamilies and perhaps rather distressingly Pereskia was not clearly monophyletic. Edwards et al. (2005) confirmed that Pereskia s.l. was probably paraphyletic, which allowed them to shed new light on the evolution of the cactus habit (cf. Butterworth & Wallace 2005 - topology different). For tmore details on the relationships of the major clades in Cactaceae, all well supported except for Pereskioideae, see Butterworth and Edwards (2008).

For relationships within Opuntioideae, see Griffith (2002), Wallace and Dickie (2002), Butterworth and Edwards (2008) and especially Griffith and Porter (2009). The latter found the well-supported set of relationships [Maihueniopsis et al. [Pterocactus [terete-stemmed species + flat-stemmed species]]]; the leafy Pereskiopsis is in a derived position in the clade (cf e.g. Mauseth 2005 on its apparently plesiomorphous features). Within Cactoideae, the distinctive Blossfeldia liliputana (= Blossfeldioideae Crozier) is perhaps sister to all other Cactoideae (Crozier 2004), and although there was initially some controversy over this position, it has been confirmed (see also Gorelick 2004; Mauseth 2006b; Butterworth 2006b). For the phylogeny of South American mountain cacti (Cactoideae), see Ritz et al. (2007). See also Wallace and Cota (1996) for the rpoCI intron and Wallace and Gibson (2002) for general relationships.

Classification. Metzing and Kiesling (2008) summarize early (pre-DNA) studies in the family, and include reproductions of some remarkable evolutionary trees. Over the years, there have been major disagreemwnts on taxon limits, and depending on the author, the number of genera occuring in the family varies by a factor of ten, and of the species by a factor of two... For example, in Cactoideae a mere sixteen genera included all the species in the subfamily 1n 1903, but now as many as 116 genera may be recognized (Hunt 2002).

Thus Wallace and Dickie (2002) have again suggested that Opuntia should be dismembered, with perhaps sixteen genera in Opuntioideae. Indeed, The situation in Opuntioideae is indeed a mess, as is clear from the recent study by Griffith and Porter (2009); Hunt (1999, 2002) had proposed the recognition of about eight broadly-delimited genera, roughly equivalent to tribes of other workers, which certainly makes sense pending sorting out the phylogeny of the group as a whole - and might also be a sensible final solution. Whether or not the stakeholders (Griffith & Porter 2009) would agree might be another matter.

For revisions of critical taxa, see work by Leuenberger, e.g. Leuenberger and Eggli (1999: Blossfeldia) and Leuenberger (1986: Pereskia and Rhodocactus, 1997: Maiheunia, 2008: update on the literature of all three).

Previous Relationships. Despite the distinctive appearance of the "leafless" cacti, the realtionships of the family with other caryophyllales has generaly been recognized.